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Pushpakumar S, Singh M, Sen U, Tyagi N, Tyagi SC. The role of the mitochondrial trans-sulfuration in cerebro-cardio renal dysfunction during trisomy down syndrome. Mol Cell Biochem 2024; 479:825-829. [PMID: 37198322 DOI: 10.1007/s11010-023-04761-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 05/05/2023] [Indexed: 05/19/2023]
Abstract
One in 700 children is born with the down syndrome (DS). In DS, there is an extra copy of X chromosome 21 (trisomy). Interestingly, the chromosome 21 also contains an extra copy of the cystathionine beta synthase (CBS) gene. The CBS activity is known to contribute in mitochondrial sulfur metabolism via trans-sulfuration pathway. We hypothesize that due to an extra copy of the CBS gene there is hyper trans-sulfuration in DS. We believe that understanding the mechanism of hyper trans-sulfuration during DS will be important in improving the quality of DS patients and towards developing new treatment strategies. We know that folic acid "1-carbon" metabolism (FOCM) cycle transfers the "1-carbon" methyl group to DNA (H3K4) via conversion of s-adenosyl methionine (SAM) to s-adenosyl homocysteine (SAH) by DNMTs (the gene writers). The demethylation reaction is carried out by ten-eleven translocation methylcytosine dioxygenases (TETs; the gene erasers) through epigenetics thus turning the genes off/on and opening the chromatin by altering the acetylation/HDAC ratio. The S-adenosyl homocysteine hydrolase (SAHH) hydrolyzes SAH to homocysteine (Hcy) and adenosine. The Hcy is converted to cystathionine, cysteine and hydrogen sulfide (H2S) via CBS/cystathioneγ lyase (CSE)/3-mercaptopyruvate sulfurtransferase (3MST) pathways. Adenosine by deaminase is converted to inosine and then to uric acid. All these molecules remain high in DS patients. H2S is a potent inhibitor of mitochondrial complexes I-IV, and regulated by UCP1. Therefore, decreased UCP1 levels and ATP production can ensue in DS subjects. Interestingly, children born with DS show elevated levels of CBS/CSE/3MST/Superoxide dismutase (SOD)/cystathionine/cysteine/H2S. We opine that increased levels of epigenetic gene writers (DNMTs) and decreased in gene erasers (TETs) activity cause folic acid exhaustion, leading to an increase in trans-sulphuration by CBS/CSE/3MST/SOD pathways. Thus, it is important to determine whether SIRT3 (inhibitor of HDAC3) can decrease the trans-sulfuration activity in DS patients. Since there is an increase in H3K4 and HDAC3 via epigenetics in DS, we propose that sirtuin-3 (Sirt3) may decrease H3K4 and HDAC3 and hence may be able to decrease the trans-sulfuration in DS. It would be worth to determine whether the lactobacillus, a folic acid producing probiotic, mitigates hyper-trans-sulphuration pathway in DS subjects. Further, as we know that in DS patients the folic acid is exhausted due to increase in CBS, Hcy and re-methylation. In this context, we suggest that folic acid producing probiotics such as lactobacillus might be able to improve re-methylation process and hence may help decrease the trans-sulfuration pathway in the DS patients.
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Affiliation(s)
- Sathnur Pushpakumar
- Department of Physiology, University of Louisville, Louisville, Kentucky, 40202, USA
| | - Mahavir Singh
- Department of Physiology, University of Louisville, Louisville, Kentucky, 40202, USA.
- School of Medicine, University of Louisville, Louisville, Kentucky, USA.
| | | | - N Tyagi
- Department of Physiology, University of Louisville, Louisville, Kentucky, 40202, USA
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville, Louisville, Kentucky, 40202, USA
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2
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Ponti AK, Silver DJ, Hine C, Lathia JD. Should I stay or should I go? Transsulfuration influences invasion and growth in glioblastoma. J Clin Invest 2024; 134:e176879. [PMID: 38299594 PMCID: PMC10836793 DOI: 10.1172/jci176879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024] Open
Abstract
A major challenge in treating patients with glioblastoma is the inability to eliminate highly invasive cells with chemotherapy, radiation, or surgical resection. As cancer cells face the issue of replicating or invading neighboring tissue, they rewire their metabolism in a concerted effort to support necessary cellular processes and account for altered nutrient abundance. In this issue of the JCI, Garcia et al. compared an innovative 3D hydrogel-based invasion device to regional patient biopsies through a comprehensive multiomics-based approach paired with a CRISPR knockout screen. Their findings elucidate a role for cystathionine γ-lyase (CTH), an enzyme in the transsulfuration pathway, as a means of regulating the cellular response to oxidative stress. CTH-mediated conversion of cystathionine to cysteine was necessary for regulating reactive oxygen species to support invasion. Meanwhile, inhibition of CTH suppressed the invasive glioblastoma phenotype. However, inhibiting CTH resulted in a larger overall tumor mass. These findings suggest that targeting the transsulfuration pathway may serve as a means of redirecting glioblastoma to proliferate or invade.
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Affiliation(s)
- András K Ponti
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine and Case Western Reserve University, Cleveland, Ohio, USA
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Daniel J Silver
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
- Case Comprehensive Cancer Center, Cleveland, Ohio, USA
- Department of Pathology, Cleveland Clinic Lerner College of Medicine and Case Western Reserve University, Cleveland, Ohio, USA
| | - Christopher Hine
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine and Case Western Reserve University, Cleveland, Ohio, USA
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
- Case Comprehensive Cancer Center, Cleveland, Ohio, USA
| | - Justin D Lathia
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine and Case Western Reserve University, Cleveland, Ohio, USA
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
- Case Comprehensive Cancer Center, Cleveland, Ohio, USA
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3
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Collard R, Majtan T. Genetic and Pharmacological Modulation of Cellular Proteostasis Leads to Partial Functional Rescue of Homocystinuria-Causing Cystathionine-Beta Synthase Variants. Mol Cell Biol 2023; 43:664-674. [PMID: 38051092 PMCID: PMC10761163 DOI: 10.1080/10985549.2023.2284147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023] Open
Abstract
Homocystinuria (HCU), an inherited metabolic disorder caused by lack of cystathionine beta-synthase (CBS) activity, is chiefly caused by misfolding of single amino acid residue missense pathogenic variants. Previous studies showed that chemical, pharmacological chaperones or proteasome inhibitors could rescue function of multiple pathogenic CBS variants; however, the underlying mechanisms remain poorly understood. Using Chinese hamster DON fibroblasts devoid of CBS and stably overexpressing human WT or mutant CBS, we showed that expression of pathogenic CBS variant mostly dysregulates gene expression of small heat shock proteins HSPB3 and HSPB8 and members of HSP40 family. Endoplasmic reticulum stress sensor BiP was found upregulated with CBS I278T variant associated with proteasomes suggesting proteotoxic stress and degradation of misfolded CBS. Co-expression of the main effector HSP70 or master regulator HSF1 rescued steady-state levels of CBS I278T and R125Q variants with partial functional rescue of the latter. Pharmacological proteostasis modulators partially rescued expression and activity of CBS R125Q likely due to reduced proteotoxic stress as indicated by decreased BiP levels and promotion of refolding as indicated by induction of HSP70. In conclusion, targeted manipulation of cellular proteostasis may represent a viable therapeutic approach for the permissive pathogenic CBS variants causing HCU.
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Affiliation(s)
- Renata Collard
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Tomas Majtan
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Pharmacology, University of Fribourg, Faculty of Science and Medicine, Fribourg, Switzerland
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4
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Dey A, Pramanik PK, Dwivedi SKD, Neizer-Ashun F, Kiss T, Ganguly A, Rice H, Mukherjee P, Xu C, Ahmad M, Csiszar A, Bhattacharya R. A role for the cystathionine-β-synthase /H 2S axis in astrocyte dysfunction in the aging brain. Redox Biol 2023; 68:102958. [PMID: 37948927 PMCID: PMC10663824 DOI: 10.1016/j.redox.2023.102958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/03/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023] Open
Abstract
Astrocytic dysfunction is central to age-related neurodegenerative diseases. However, the mechanisms leading to astrocytic dysfunction are not well understood. We identify that among the diverse cellular constituents of the brain, murine and human astrocytes are enriched in the expression of CBS. Depleting CBS in astrocytes causes mitochondrial dysfunction, increases the production of reactive oxygen species (ROS) and decreases cellular bioenergetics that can be partially rescued by exogenous H2S supplementation or by re-expressing CBS. Conversely, the CBS/H2S axis, associated protein persulfidation and proliferation are decreased in astrocytes upon oxidative stress which can be rescued by exogenous H2S supplementation. Here we reveal that in the aging brain, the CBS/H2S axis is downregulated leading to decreased protein persulfidation, together augmenting oxidative stress. Our findings uncover an important protective role of the CBS/H2S axis in astrocytes that may be disrupted in the aged brain.
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Affiliation(s)
- Anindya Dey
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Pijush Kanti Pramanik
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Shailendra Kumar Dhar Dwivedi
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA; Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Fiifi Neizer-Ashun
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Tamas Kiss
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Pediatric Center, Semmelweis University, Budapest, Hungary
| | - Abhrajit Ganguly
- Section of Neonatal-Perinatal Medicine, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Heather Rice
- Department of Biochemistry & Molecular Biology, Oklahoma Center for Geroscience & Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Priyabrata Mukherjee
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA; Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Chao Xu
- Department of Biostatistics and Epidemiology, Hudson College of Public Health, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Mohiuddin Ahmad
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Resham Bhattacharya
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA; Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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5
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Dong B, Sun Y, Cheng B, Xue Y, Li W, Sun X. Activating transcription factor (ATF) 6 upregulates cystathionine β synthetase (CBS) expression and hydrogen sulfide (H 2S) synthesis to ameliorate liver metabolic damage. Eur J Med Res 2023; 28:540. [PMID: 38007457 PMCID: PMC10676581 DOI: 10.1186/s40001-023-01520-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 11/09/2023] [Indexed: 11/27/2023] Open
Abstract
Activating transcription factor 6 (ATF6) is an endoplasmic reticulum stress responsive gene. We previously reported that conditional knockout of hepatic ATF6 exacerbated liver metabolic damage by repressing autophagy through mTOR pathway. However, the mechanism by which ATF6 influence liver metabolism has not been well established. Hydrogen sulfide (H2S) is a gaseous signaling molecule that plays an important role in regulating inflammation, and suppress nonalcoholic fatty liver in mice. Based on the previous study, we assumed that ATF6 may regulate H2S production to participate in liver metabolism. In order to clarify the mechanism by which ATF6 regulates H2S synthesis to ameliorate liver steatosis and inflammatory environment, we conducted the present study. We used the liver specific ATF6 knockout mice and fed on high-fat-diet, and found that H2S level was significantly downregulated in hepatic ATF6 knockout mice. Restoring H2S by the administration of slow H2S releasing agent GYY4137 ameliorated the hepatic steatosis and glucose tolerance. ATF6 directly binds to the promoter of cystathionine β synthetase (CBS), an important enzyme in H2S synthesis. Thus, ATF6 could upregulate H2S production through CBS. Sulfhydrated Sirtuin-1 (SIRT1) was downregulated in ATF6 knockout mice. The expression of pro-inflammatory factor IL-17A was upregulated and anti-inflammatory factor IL-10 was downregulated in ATF6 knockout mice. Our results suggest that ATF6 can transcriptionally enhance CBS expression as well as H2S synthesis. ATF6 increases SIRT1 sulfhydration and ameliorates lipogenesis and inflammation in the fatty liver. Therefore, ATF6 could be a novel therapeutic strategy for high-fat diet induced fatty liver metabolic abnormalities.
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Affiliation(s)
- Bingzi Dong
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Ying Sun
- Health Management Center, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Bingfei Cheng
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Yu Xue
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Wei Li
- Interventional Medical Center, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Xiaofang Sun
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China.
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6
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Conter C, Favretto F, Dominici P, Martinez-Cruz LA, Astegno A. Key substrate recognition residues in the active site of cystathionine beta-synthase from Toxoplasma gondii. Proteins 2023; 91:1383-1393. [PMID: 37163386 DOI: 10.1002/prot.26507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/28/2023] [Accepted: 04/19/2023] [Indexed: 05/12/2023]
Abstract
Cystathionine β-synthase (CBS) catalyzes the condensation of l-serine and l-homocysteine to give l-cystathionine in the transsulfuration pathway. Recently, a few O-acetylserine (l-OAS)-dependent CBSs (OCBSs) have been found in bacteria that can exclusively function with l-OAS. CBS from Toxoplasma gondii (TgCBS) can efficiently use both l-serine and l-OAS to form l-cystathionine. In this work, a series of site-specific variants substituting S84, Y160, and Y246 with hydrophobic residues found at the same positions in OCBSs was generated to explore the roles of the hydroxyl moieties of these residues as determinants of l-serine/l-OAS preference in TgCBS. We found that the S84A/Y160F/Y246V triple mutant behaved like an OCBS in terms of both substrate requirements, showing β-replacement activity only with l-OAS, and pH optimum, which is decreased by ~1 pH unit. Formation of a stable aminoacrylate upon reaction with l-serine is prevented by the triple mutation, indicating the importance of the H-bonds between the hydroxyl groups of Y160, Y246, and S84 with l-serine in formation of the intermediate. Analysis of the independent effect of each mutation on TgCBS activity and investigation of the protein-aminoacrylate complex structure allowed for the conclusion that the hydroxyl group of Y246 has a major, but not exclusive, role in controlling the l-serine preference by efficiently stabilizing its leaving group. These studies demonstrate that differences in substrate specificity of CBSs are controlled by natural variations in as few as three residue positions. A better understanding of substrate specificity in TgCBS will facilitate the design of new antimicrobial compounds.
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Affiliation(s)
- Carolina Conter
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Filippo Favretto
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Luis Alfonso Martinez-Cruz
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Derio, Spain
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7
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Dalkir FT, Aydinoglu F, Ogulener N. The role of rhoA/rho-kinase and PKC in the inhibitory effect of L-cysteine/H 2S pathway on the carbachol-mediated contraction of mouse bladder smooth muscle. Naunyn Schmiedebergs Arch Pharmacol 2023; 396:2023-2038. [PMID: 36894621 DOI: 10.1007/s00210-023-02440-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 02/20/2023] [Indexed: 03/11/2023]
Abstract
We investigated the role of RhoA/Rho-kinase (ROCK) and PKC in the inhibitory effect of L-cysteine/hydrogen sulfide (H2S) pathway on the carbachol-mediated contraction of mouse bladder smooth muscle. Carbachol (10-8-10-4 M) induced a concentration-dependent contraction in bladder tissues. L-cysteine (H2S precursor; 10-2 M) and exogenous H2S (NaHS; 10-3 M) reduced the contractions evoked by carbachol by ~ 49 and ~ 53%, respectively, relative to control. The inhibitory effect of L-cysteine on contractions to carbachol was reversed by 10-2 M PAG (~ 40%) and 10-3 M AOAA (~ 55%), cystathionine-gamma-lyase (CSE) and cystathionine-β-synthase (CBS) inhibitor, respectively. Y-27632 (10-6 M) and GF 109203X (10-6 M), a specific ROCK and PKC inhibitor, respectively, reduced contractions evoked by carbachol (~ 18 and ~ 24% respectively), and the inhibitory effect of Y-27632 and GF 109203X on contractions was reversed by PAG (~ 29 and ~ 19%, respectively) but not by AOAA. Also, Y-27632 and GF 109203X reduced the inhibitory responses of L-cysteine on the carbachol-induced contractions (~ 38 and ~ 52% respectively), and PAG abolished the inhibitory effect of L-cysteine on the contractions in the presence of Y-27632 (~ 38%). Also, the protein expressions of CSE, CBS, and 3-MST enzymes responsible for endogenous H2S synthesis were detected by Western blot method. H2S level was increased by L-cysteine, Y-27632, and GF 109203X (from 0.12 ± 0.02 to 0.47 ± 0.13, 0.26 ± 0.03, and 0.23 ± 0.06 nmol/mg respectively), and this augmentation in H2S level decreased with PAG (0.17 ± 0.02, 0.15 ± 0.03, and 0.07 ± 0.04 nmol/mg respectively). Furthermore, L-cysteine and NaHS reduced carbachol-induced ROCK-1, pMYPT1, and pMLC20 levels. Inhibitory effects of L-cysteine on ROCK-1, pMYPT1, and pMLC20 levels, but not of NaHS, were reversed by PAG. These results suggest that there is an interaction between L-cysteine/H2S and RhoA/ROCK pathway via inhibition of ROCK-1, pMYPT1, and pMLC20, and the inhibition of RhoA/ROCK and/or PKC signal pathway may be mediated by the CSE-generated H2S in mouse bladder.
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Affiliation(s)
- Fatma Tugce Dalkir
- Department of Pharmacology, Medical Faculty, Cukurova University, Adana, Turkey
| | - Fatma Aydinoglu
- Department of Pharmacology, Pharmacy Faculty, Cukurova University, Adana, Turkey
| | - Nuran Ogulener
- Department of Pharmacology, Medical Faculty, Cukurova University, Adana, Turkey.
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8
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Aboragah AA, Alharthi AS, Wichasit N, Loor JJ. Body condition prepartum and its association with term placentome nutrient transporters, one‑carbon metabolism pathway activity, and intermediate metabolites in Holstein cows. Res Vet Sci 2023; 162:104956. [PMID: 37516040 DOI: 10.1016/j.rvsc.2023.104956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 06/27/2023] [Accepted: 07/10/2023] [Indexed: 07/31/2023]
Abstract
We investigated linkages among BCS prior to calving and placentome concentrations of metabolites, proteins in one‑carbon metabolism (OCM) and protein synthesis, and nutrient transport. Multiparous Holstein cows retrospectively divided by prepartal BCS at -4 weeks relative to parturition into high BCS (HBCS = 3.58 ± 0.23; n = 9) or normal BCS (NBCS = 3.02 ± 0.17; n = 13) were used. BCS was assessed using a 5-point scale (1 = thin, 5 = fat). Four placentomes per cow were collected at delivery and frozen in liquid N. Western blotting was used for protein abundance. Cystathionine-β-synthase (CBS) and betaine-homocysteine-S-methyltransferase (BHMT) activity were measured via 14C assays. Amino acids (AA) and metabolites in OCM were measured by liquid chromatography mass spectrometry (LC-MS). Compared with NBCS cows, the cellular stress sensor p-eIF2α was more than 2-fold greater (P = 0.04) in HBCS. Abundance of the AA-catabolism enzyme branched-chain α-ketoacid dehydrogenase complex was lower (P = 0.05) in HBCS cows. Although BHMT activity did not differ, greater concentration of betaine (P = 0.01) and lower (P = 0.05) concentration of dimethylglycine in HBCS cows suggested reduced flux through the methionine cycle. Despite a lack of difference in CBS activity, lower concentrations of cystathionine (P = 0.03) and hypotaurine (P = 0.04) along with lower cysteine and the tendency for lower total GSH (P = 0.10) in HBCS cows suggested a decrease in transsulfuration. Overall, associations between OCM in placentomes and BCS at calving exist. Identifying mechanisms responsible for these effects merits further research.
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Affiliation(s)
- Ahmad A Aboragah
- Department of Animal Sciences, University of Illinois, Urbana 61801, USA; Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Abdulrahman S Alharthi
- Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Nithat Wichasit
- Department of Animal Sciences, University of Illinois, Urbana 61801, USA; Department of Agricultural Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Juan J Loor
- Department of Animal Sciences, University of Illinois, Urbana 61801, USA; Division of Nutritional Sciences, University of Illinois, Urbana 61801, USA.
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9
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Tran CM, Mihara S, Yoshida K, Hisabori T. Cystathionine-β-synthase X proteins negatively regulate NADPH-thioredoxin reductase C activity. Biochem Biophys Res Commun 2023; 653:47-52. [PMID: 36857899 DOI: 10.1016/j.bbrc.2023.02.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 02/20/2023] [Indexed: 02/23/2023]
Abstract
Redox regulation is a posttranslational modification based on the redox reaction of protein thiols. A small ubiquitous protein thioredoxin (Trx) plays a central role in redox regulation, but a unique redox-regulatory factor called NADPH-Trx reductase C (NTRC) is also found in plant chloroplasts and some cyanobacteria. Several important functions of NTRC have been suggested, but the mechanism for controlling NTRC activity remains undetermined. Cystathionine-β-synthase X (CBSX) proteins have been previously shown to interact with NTRC physically. Based on these observations, this study biochemically investigated the functional interaction between CBSX proteins and NTRC from Arabidopsis thaliana in vitro. Consequently, we concluded that CBSX proteins act as negative regulators of NTRC in the presence of AMP.
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Affiliation(s)
- Chau M Tran
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8503, Japan
| | - Shoko Mihara
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8503, Japan
| | - Keisuke Yoshida
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8503, Japan.
| | - Toru Hisabori
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8503, Japan.
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10
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Matoba Y, Noda M, Yoshida T, Oda K, Ezumi Y, Yasutake C, Izuhara-Kihara H, Danshiitsoodol N, Kumagai T, Sugiyama M. Catalytic specificity of the Lactobacillus plantarum cystathionine γ-lyase presumed by the crystallographic analysis. Sci Rep 2020; 10:14886. [PMID: 32913258 DOI: 10.1038/s51598-020-71756-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/05/2020] [Indexed: 05/22/2023] Open
Abstract
The reverse transsulfuration pathway, which is composed of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CGL), plays a role to synthesize L-cysteine using L-serine and the sulfur atom in L-methionine. A plant-derived lactic acid bacterium Lactobacillus plantarum SN35N has been previously found to harbor the gene cluster encoding the CBS- and CGL-like enzymes. In addition, it has been demonstrated that the L. plantarum CBS can synthesize cystathionine from O-acetyl-L-serine and L-homocysteine. The aim of this study is to characterize the enzymatic functions of the L. plantarum CGL. We have found that the enzyme has the high γ-lyase activity toward cystathionine to generate L-cysteine, together with the β-lyase activity toward L-cystine to generate L-cysteine persulfide. By the crystallographic analysis of the inactive CGL K194A mutant complexed with cystathionine, we have found the residues which recognize the distal amino and carboxyl groups of cystathionine or L-cystine. The PLP-bound substrates at the active site may take either the binding pose for the γ- or β-elimination reaction, with the former being the major reaction in the case of cystathionine.
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Affiliation(s)
- Yasuyuki Matoba
- Faculty of Pharmacy, Yasuda Women's University, Yasuhigashi 6-13-1, Asaminami-ku, Hiroshima, 731-0153, Japan.
| | - Masafumi Noda
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
| | - Tomoki Yoshida
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
| | - Kosuke Oda
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
| | - Yuka Ezumi
- Faculty of Pharmacy, Yasuda Women's University, Yasuhigashi 6-13-1, Asaminami-ku, Hiroshima, 731-0153, Japan
| | - Chiaki Yasutake
- Faculty of Pharmaceutical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
| | - Hisae Izuhara-Kihara
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
| | - Narandarai Danshiitsoodol
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
| | - Takanori Kumagai
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan
| | - Masanori Sugiyama
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan.
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11
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Bronowicka-Adamska P, Hutsch T, Gawryś-Kopczyńska M, Maksymiuk K, Wróbel M. Hydrogen sulfide formation in experimental model of acute pancreatitis. Acta Biochim Pol 2019; 66:611-618. [PMID: 31893496 DOI: 10.18388/abp.2019_2900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/04/2019] [Indexed: 11/10/2022]
Abstract
Acute pancreatitis (AP) is a disease defined as acute or chronic inflammatory process of the pancreas characterized by premature activation of digestive enzymes within the pancreatic acinar cells and causing pancreatic auto-digestion. In mammalian tissues, H2S is synthesized endogenously from L-cysteine in regulated enzymatic pathways catalyzed by pyridoxal phosphate-dependent enzymes: cystathionine beta - synthase (CBS), gamma - cystathionase (CTH) and cysteine aminotransferase (CAT) coupled with 3-mercaptopyruvate sulfurtransferase (MPST). In the mitochondria, hydrogen sulfide is oxidized to sulfite, which is then converted to thiosulfate (sulfane sulfur-containing compound) by thiosulfate sulfurtransferase (rhodanese; TST). The activity and the expression of CBS, CTH, MPST, and TST have been determined in vivo in pancreas of control rats, rats with acute pancreatitis and sham group. Levels of low-molecular sulfur compounds such as reduced and oxidized glutathione, cysteine, cystine and cystathionine were also determined. The study showed the significant role of MPST in H2S metabolism in pancreas. Stress caused by the surgery (sham group) and AP cause a decrease in H2S production associated with a decrease of MPST activity and expression. Markedly higher level of cysteine in the AP pancreas may be caused by a reduced rate of cysteine consumption in reaction catalyzed by MPST but it can also be a sign of the processes of proteolysis occurring in the changed tissue.
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Affiliation(s)
| | - Tomasz Hutsch
- Department of Physiology and Experimental Pathophysiology, Medical University of Warsaw, Warsaw, Poland
| | - Marta Gawryś-Kopczyńska
- Department of Physiology and Experimental Pathophysiology, Medical University of Warsaw, Warsaw, Poland
| | - Klaudia Maksymiuk
- Department of Physiology and Experimental Pathophysiology, Medical University of Warsaw, Warsaw, Poland
| | - Maria Wróbel
- Chair of Medical Biochemistry, Jagiellonian University, Collegium Modicum, Kraków, Poland
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12
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Kasak L, Bakolitsa C, Hu Z, Yu C, Rine J, Dimster-Denk DF, Pandey G, Baets GD, Bromberg Y, Cao C, Capriotti E, Casadio R, Durme JV, Giollo M, Karchin R, Katsonis P, Leonardi E, Lichtarge O, Martelli PL, Masica D, Mooney SD, Olatubosun A, Pal LR, Radivojac P, Rousseau F, Savojardo C, Schymkowitz J, Thusberg J, Tosatto SC, Vihinen M, Väliaho J, Repo S, Moult J, Brenner SE, Friedberg I. Assessing computational predictions of the phenotypic effect of cystathionine-beta-synthase variants. Hum Mutat 2019; 40:1530-1545. [PMID: 31301157 PMCID: PMC7325732 DOI: 10.1002/humu.23868] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/22/2019] [Accepted: 07/09/2019] [Indexed: 12/28/2022]
Abstract
Accurate prediction of the impact of genomic variation on phenotype is a major goal of computational biology and an important contributor to personalized medicine. Computational predictions can lead to a better understanding of the mechanisms underlying genetic diseases, including cancer, but their adoption requires thorough and unbiased assessment. Cystathionine-beta-synthase (CBS) is an enzyme that catalyzes the first step of the transsulfuration pathway, from homocysteine to cystathionine, and in which variations are associated with human hyperhomocysteinemia and homocystinuria. We have created a computational challenge under the CAGI framework to evaluate how well different methods can predict the phenotypic effect(s) of CBS single amino acid substitutions using a blinded experimental data set. CAGI participants were asked to predict yeast growth based on the identity of the mutations. The performance of the methods was evaluated using several metrics. The CBS challenge highlighted the difficulty of predicting the phenotype of an ex vivo system in a model organism when classification models were trained on human disease data. We also discuss the variations in difficulty of prediction for known benign and deleterious variants, as well as identify methodological and experimental constraints with lessons to be learned for future challenges.
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Affiliation(s)
- Laura Kasak
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Constantina Bakolitsa
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Zhiqiang Hu
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Changhua Yu
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Jasper Rine
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Dago F. Dimster-Denk
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Gaurav Pandey
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Greet De Baets
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Yana Bromberg
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA
| | - Chen Cao
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
- Computational Biology, Bioinformatics and Genomics, Biological Sciences Graduate Program, University of Maryland, College Park, MD, USA
| | - Emidio Capriotti
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Rita Casadio
- Biocomputing Group, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Joost Van Durme
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium
- Vrije Universiteit Brussel, Brussels, Belgium
| | - Manuel Giollo
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Rachel Karchin
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Panagiotis Katsonis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Pier Luigi Martelli
- Biocomputing Group, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - David Masica
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | | | - Ayodeji Olatubosun
- Institute of Medical Technology, University of Tampere, Tampere, Finland
| | - Lipika R. Pal
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Predrag Radivojac
- School of Informatics and Computing, Indiana University, Bloomington, IN, USA
| | - Frederic Rousseau
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Castrense Savojardo
- Biocomputing Group, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Joost Schymkowitz
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | | | | | - Mauno Vihinen
- Institute of Medical Technology, University of Tampere, Tampere, Finland
| | - Jouni Väliaho
- Institute of Medical Technology, University of Tampere, Tampere, Finland
| | - Susanna Repo
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - John Moult
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Steven E. Brenner
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Iddo Friedberg
- Department of Microbiology, Miami University, Oxford, OH, USA
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA USA
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13
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Olsen T, Øvrebø B, Turner C, Bastani NE, Refsum H, Vinknes KJ. Combining Dietary Sulfur Amino Acid Restriction with Polyunsaturated Fatty Acid Intake in Humans: A Randomized Controlled Pilot Trial. Nutrients 2018; 10:nu10121822. [PMID: 30477080 PMCID: PMC6315936 DOI: 10.3390/nu10121822] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 01/09/2023] Open
Abstract
Dietary and plasma total cysteine (tCys) have been associated with adiposity, possibly through interaction with stearoyl–CoA desaturase (SCD), which is an enzyme that is involved in fatty acid and energy metabolism. We evaluated the effect of a dietary intervention with low cysteine and methionine and high polyunsaturated fatty acids (PUFAs) on plasma and urinary sulfur amino acids and SCD activity indices. Fourteen normal-weight healthy subjects were randomized to a seven-day diet low in cysteine and methionine and high in PUFAs (Cys/Metlow + PUFA), or high in saturated fatty acids (SFA), cysteine, and methionine (Cys/Methigh + SFA). Compared with the Cys/Methigh + SFA group, plasma methionine and cystathionine decreased (p-values < 0.05), whereas cystine tended to increase (p = 0.06) in the Cys/Metlow + PUFA group. Plasma total cysteine (tCys) was not significantly different between the groups. Urinary cysteine and taurine decreased in the Cys/Metlow + PUFA group compared with the Cys/Methigh + SFA group (p-values < 0.05). Plasma SCD-activity indices were not different between the groups, but the change in cystine correlated with the SCD-16 index in the Cys/Metlow + PUFA group. A diet low in methionine and cysteine decreased plasma methionine and urinary cysteine and taurine. Plasma tCys was unchanged, suggesting that compensatory mechanisms are activated during methionine and cysteine restriction to maintain plasma tCys.
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Affiliation(s)
- Thomas Olsen
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway.
| | - Bente Øvrebø
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway.
- Øvrebø Nutrition, 0550 Oslo, Norway.
| | - Cheryl Turner
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK.
| | - Nasser E Bastani
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway.
| | - Helga Refsum
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway.
| | - Kathrine J Vinknes
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway.
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14
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Ernst DC, Christopherson MR, Downs DM. Increased Activity of Cystathionine β-Lyase Suppresses 2-Aminoacrylate Stress in Salmonella enterica. J Bacteriol 2018; 200:e00040-18. [PMID: 29440255 PMCID: PMC5892115 DOI: 10.1128/jb.00040-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 02/08/2018] [Indexed: 01/07/2023] Open
Abstract
Reactive enamine stress caused by intracellular 2-aminoacrylate accumulation leads to pleiotropic growth defects in a variety of organisms. Members of the well-conserved RidA/YER057c/UK114 protein family prevent enamine stress by enhancing the breakdown of 2-aminoacrylate to pyruvate. In Salmonella enterica, disruption of RidA allows 2-aminoacrylate to accumulate and to inactivate a variety of pyridoxal 5'-phosphate-dependent enzymes by generating covalent bonds with the enzyme and/or cofactor. This study was initiated to identify mechanisms that can overcome 2-aminoacrylate stress in the absence of RidA. Multicopy suppressor analysis revealed that overproduction of the methionine biosynthesis enzyme cystathionine β-lyase (MetC) (EC 4.4.1.8) alleviated the pleiotropic consequences of 2-aminoacrylate stress in a ridA mutant strain. Degradation of cystathionine by MetC was not required for suppression of ridA phenotypes. The data support a model in which MetC acts on a noncystathionine substrate to generate a metabolite that reduces 2-aminoacrylate levels, representing a nonenzymatic mechanism of 2-aminoacrylate depletion.IMPORTANCE RidA proteins are broadly conserved and have been demonstrated to deaminate 2-aminoacrylate and other enamines. 2-Aminoacrylate is generated as an obligatory intermediate in several pyridoxal 5'-phosphate-dependent reactions; if it accumulates, it damages cellular enzymes. This study identified a novel mechanism to eliminate 2-aminoacrylate stress that required the overproduction, but not the canonical activity, of cystathionine β-lyase. The data suggest that a metabolite-metabolite interaction is responsible for quenching 2-aminoacrylate, and they emphasize the need for emerging technologies to probe metabolism in vivo.
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Affiliation(s)
- Dustin C Ernst
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | | | - Diana M Downs
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
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15
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Allegrini A, Astegno A, La Verde V, Dominici P. Characterization of C-S lyase from Lactobacillus delbrueckii subsp. bulgaricus ATCC BAA-365 and its potential role in food flavour applications. J Biochem 2017; 161:349-360. [PMID: 28003427 DOI: 10.1093/jb/mvw079] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/17/2016] [Indexed: 01/07/2023] Open
Abstract
Volatile thiols have substantial impact on the aroma of many beverages and foods. Thus, the control of their formation, which has been linked to C-S lyase enzymatic activities, is of great significance in industrial applications involving food flavours. Herein, we have carried out a spectroscopic and functional characterization of a putative pyridoxal 5'-phosphate (PLP)-dependent C-S lyase from the lactic acid bacterium Lactobacillus delbrueckii subsp. bulgaricus ATCC BAA-365 (LDB C-S lyase). Recombinant LDB C-S lyase exists as a tetramer in solution and shows spectral properties of enzymes containing PLP as cofactor. The enzyme has a broad substrate specificity toward sulphur-containing amino acids with aminoethyl-L-cysteine and L-cystine being the most effective substrates over L-cysteine and L-cystathionine. Notably, the protein also reveals cysteine-S-conjugate β-lyase activity in vitro, and is able to cleave a cysteinylated substrate precursor into the corresponding flavour-contributing thiol, with a catalytic efficiency higher than L-cystathionine. Contrary to similar enzymes of other lactic acid bacteria however, LDB C-S lyase is not capable of α,γ-elimination activity towards L-methionine to produce methanethiol, which is a significant compound in flavour development. Based on our results, future developments can be expected regarding the flavour-forming potential of Lactobacillus C-S lyase and its use in enhancing food flavours.
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16
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Bronowicka-Adamska P, Bentke A, Wróbel M. Hydrogen sulfide generation from l-cysteine in the human glioblastoma-astrocytoma U-87 MG and neuroblastoma SHSY5Y cell lines. Acta Biochim Pol 2017; 64:171-176. [PMID: 28291844 DOI: 10.18388/abp.2016_1394] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/07/2016] [Accepted: 11/05/2016] [Indexed: 11/10/2022]
Abstract
Hydrogen sulfide (H2S) is endogenously synthesized from l-cysteine in reactions catalyzed by cystathionine beta-synthase (CBS, EC 4.2.1.22) and gamma-cystathionase (CSE, EC 4.4.1.1). The role of 3-mercaptopyruvate sulfurtransferase (MPST, EC 2.8.1.2) in H2S generation is also considered; it could be important for tissues with low CTH activity, e.g. cells of the nervous system. The expression and activity of CBS, CTH, and MPST were detected in the human glioblastoma-astrocytoma (U-87 MG) and neuroblastoma (SHSY5Y) cell lines. In both cell lines, the expression and activity of MPST were the highest among the investigated enzymes, suggesting its possible role in the generation of H2S. The RP-HPLC method was used to determine the concentration of cystathionine and alpha-ketobutyrate, products of the CBS- and CTH-catalyzed reactions. The difference in cystathionine levels between cell homogenates treated with totally CTH-inhibiting concentrations of dl-propargylglycine and without the inhibitor was used to evaluate the activity of CBS. The higher expression and activity of CBS, CTH and MPST in the neuroblastoma cells were associated with more intensive generation of H2S in the presence of 2 mM cysteine. A threefold higher level of sulfane sulfur, a potential source of hydrogen sulfide, was detected in the astrocytoma cells in comparison to the neuroblastoma cells.
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Affiliation(s)
| | - Anna Bentke
- Chair of Medical Biochemistry, Jagiellonian University, Collegium Medicum, Kraków, Poland
| | - Maria Wróbel
- Chair of Medical Biochemistry, Jagiellonian University, Collegium Medicum, Kraków, Poland
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17
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Yan W, Stone E, Zhang YJ. Structural Snapshots of an Engineered Cystathionine-γ-lyase Reveal the Critical Role of Electrostatic Interactions in the Active Site. Biochemistry 2017; 56:876-885. [PMID: 28106980 PMCID: PMC5376214 DOI: 10.1021/acs.biochem.6b01172] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enzyme therapeutics that can degrade l-methionine (l-Met) are of great interest as numerous malignancies are exquisitely sensitive to l-Met depletion. To exhaust the pool of methionine in human serum, we previously engineered an l-Met-degrading enzyme based on the human cystathionine-γ-lyase scaffold (hCGL-NLV) to circumvent immunogenicity and stability issues observed in the preclinical application of bacterially derived methionine-γ-lyases. To gain further insights into the structure-activity relationships governing the chemistry of the hCGL-NLV lead molecule, we undertook a biophysical characterization campaign that captured crystal structures (2.2 Å) of hCGL-NLV with distinct reaction intermediates, including internal aldimine, substrate-bound, gem-diamine, and external aldimine forms. Curiously, an alternate form of hCGL-NLV that crystallized under higher-salt conditions revealed a locally unfolded active site, correlating with inhibition of activity as a function of ionic strength. Subsequent mutational and kinetic experiments pinpointed that a salt bridge between the phosphate of the essential cofactor pyridoxal 5'-phosphate (PLP) and residue R62 plays an important role in catalyzing β- and γ-eliminations. Our study suggests that solvent ions such as NaCl disrupt electrostatic interactions between R62 and PLP, decreasing catalytic efficiency.
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Affiliation(s)
- Wupeng Yan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Everett Stone
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Yan Jessie Zhang
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, United States
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18
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Sorolla MA, Rodríguez-Colman MJ, Vall-Llaura N, Vived C, Fernández-Nogales M, Lucas JJ, Ferrer I, Cabiscol E. Impaired PLP-dependent metabolism in brain samples from Huntington disease patients and transgenic R6/1 mice. Metab Brain Dis 2016; 31:579-86. [PMID: 26666246 DOI: 10.1007/s11011-015-9777-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/09/2015] [Indexed: 11/25/2022]
Abstract
Oxidative stress has been described as important to Huntington disease (HD) progression. In a previous HD study, we identified several carbonylated proteins, including pyridoxal kinase and antiquitin, both of which are involved in the metabolism of pyridoxal 5´-phosphate (PLP), the active form of vitamin B6. In the present study, pyridoxal kinase levels were quantified and showed to be decreased both in HD patients and a R6/1 mouse model, compared to control samples. A metabolomic analysis was used to analyze metabolites in brain samples of HD patients and R6/1 mice, compared to control samples using mass spectrometry. This technique allowed detection of increased concentrations of pyridoxal, the substrate of pyridoxal kinase. In addition, PLP, the product of the reaction, was decreased in striatum from R6/1 mice. Furthermore, glutamate and cystathionine, both substrates of PLP-dependent enzymes were increased in HD. This reinforces the hypothesis that PLP synthesis is impaired, and could explain some alterations observed in the disease. Together, these results identify PLP as a potential therapeutic agent.
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Affiliation(s)
- M Alba Sorolla
- Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain.
| | - María José Rodríguez-Colman
- Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Núria Vall-Llaura
- Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Celia Vived
- Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Marta Fernández-Nogales
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - José J Lucas
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Isidre Ferrer
- Institut de Neuropatologia, Servei Anatomia Patològica, IDIBELL-Hospital Universitari de Bellvitge, Universitat de Barcelona, Barcelona, Spain
| | - Elisa Cabiscol
- Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
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19
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Jung J, Ha TK, Lee J, Lho Y, Nam M, Lee D, le Roux CW, Ryu DH, Ha E, Hwang GS. Changes in one-carbon metabolism after duodenal-jejunal bypass surgery. Am J Physiol Endocrinol Metab 2016; 310:E624-E632. [PMID: 26786776 DOI: 10.1152/ajpendo.00260.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 01/06/2016] [Indexed: 01/06/2023]
Abstract
Bariatric surgery alleviates obesity and ameliorates glucose tolerance. Using metabolomic and proteomic profiles, we evaluated metabolic changes in serum and liver tissue after duodenal-jejunal bypass (DJB) surgery in rats fed a normal chow diet. We found that the levels of vitamin B12 in the sera of DJB rates were decreased. In the liver of DJB rats, betaine-homocysteine S-methyltransferase levels were decreased, whereas serine, cystathionine, cysteine, glutathione, cystathionine β-synthase, glutathione S-transferase, and aldehyde dehydrogenase levels were increased. These results suggested that DJB surgery enhanced trans-sulfuration and its consecutive reactions such as detoxification and the scavenging activities of reactive oxygen species. In addition, DJB rats showed higher levels of purine metabolites such as ATP, ADP, AMP, and inosine monophosphate. Decreased guanine deaminase, as well as lower levels of hypoxanthine, indicated that DJB surgery limited the purine degradation process. In particular, the AMP/ATP ratio and phosphorylation of AMP-activated protein kinase increased after DJB surgery, which led to enhanced energy production and increased catabolic pathway activity, such as fatty acid oxidation and glucose transport. This study shows that bariatric surgery altered trans-sulfuration and purine metabolism in the liver. Characterization of these mechanisms increases our understanding of the benefits of bariatric surgery.
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Affiliation(s)
- Jeeyoun Jung
- Integrated Metabolomics Research Group, Seoul Western Center, Korea Basic Science Institute, Seoul, Republic of Korea
- KM Fundamental Research Division, Korea Institute of Oriental Medicine, Daejeon, Republic of Korea
| | - Tae Kyung Ha
- Department of Surgery, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - Jueun Lee
- Integrated Metabolomics Research Group, Seoul Western Center, Korea Basic Science Institute, Seoul, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon, Republic of Korea
| | - Yunmee Lho
- Department of Biochemistry, School of Medicine, Keimyung University, Daegu, Republic of Korea
| | - Miso Nam
- Integrated Metabolomics Research Group, Seoul Western Center, Korea Basic Science Institute, Seoul, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon, Republic of Korea
| | - Doohae Lee
- Integrated Metabolomics Research Group, Seoul Western Center, Korea Basic Science Institute, Seoul, Republic of Korea
| | - Carel W le Roux
- Diabetes Complications Research Center, UCD Conway Institute, School of Medicine and Medical Science, University College Dublin, Ireland; and
| | - Do Hyun Ryu
- Department of Chemistry, Sungkyunkwan University, Suwon, Republic of Korea
| | - Eunyoung Ha
- Department of Biochemistry, School of Medicine, Keimyung University, Daegu, Republic of Korea
| | - Geum-Sook Hwang
- Integrated Metabolomics Research Group, Seoul Western Center, Korea Basic Science Institute, Seoul, Republic of Korea
- Department of Life Science, Ewha Womans University, Seoul, Republic of Korea
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Kožich V, Krijt J, Sokolová J, Melenovská P, Ješina P, Vozdek R, Majtán T, Kraus JP. Thioethers as markers of hydrogen sulfide production in homocystinurias. Biochimie 2016; 126:14-20. [PMID: 26791043 DOI: 10.1016/j.biochi.2016.01.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 01/08/2016] [Indexed: 01/20/2023]
Abstract
Two enzymes in the transsulfuration pathway of homocysteine -cystathionine beta-synthase (CBS) and gamma-cystathionase (CTH)-use cysteine and/or homocysteine to produce the important signaling molecule hydrogen sulfide (H2S) and simultaneously the thioethers lanthionine, cystathionine or homolanthionine. In this study we explored whether impaired flux of substrates for H2S synthesis and/or deficient enzyme activities alter production of hydrogen sulfide in patients with homocystinurias. As an indirect measure of H2S synthesis we determined by LC-MS/MS concentrations of thioethers in plasma samples from 33 patients with different types of homocystinurias, in 8 patient derived fibroblast cell lines, and as reaction products of seven purified mutant CBS enzymes. Since chaperoned recombinant mutant CBS enzymes retained capacity of H2S synthesis in vitro it can be stipulated that deficient CBS activity in vivo may impair H2S production. Indeed, in patients with classical homocystinuria we observed significantly decreased cystathionine and lanthionine concentrations in plasma (46% and 74% of median control levels, respectively) and significantly lower cystathionine in fibroblasts (8% of median control concentrations) indicating that H2S production from cysteine and homocysteine may be also impaired. In contrast, the grossly elevated plasma levels of homolanthionine in CBS deficient patients (32-times elevation compared to median of controls) clearly demonstrates a simultaneous overproduction of H2S from homocysteine by CTH. In the remethylation defects the accumulation of homocysteine and the increased flux of metabolites through the transsulfuration pathway resulted in elevation of cystathionine and homolanthionine (857% and 400% of median control values, respectively) indicating a possibility of an increased biosynthesis of H2S by both CBS and CTH. This study shows clearly disturbed thioether concentrations in homocystinurias, and modeling using these data indicates that H2S synthesis may be increased in these conditions. Further studies are needed to confirm our findings and to explore the possible implications for pathophysiology of these disorders.
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Affiliation(s)
- Viktor Kožich
- Institute of Inherited Metabolic Disorders, Charles University in Prague-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic.
| | - Jakub Krijt
- Institute of Inherited Metabolic Disorders, Charles University in Prague-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Jitka Sokolová
- Institute of Inherited Metabolic Disorders, Charles University in Prague-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Petra Melenovská
- Institute of Inherited Metabolic Disorders, Charles University in Prague-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Pavel Ješina
- Institute of Inherited Metabolic Disorders, Charles University in Prague-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Roman Vozdek
- Institute of Inherited Metabolic Disorders, Charles University in Prague-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Tomáš Majtán
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Jan P Kraus
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
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Abstract
Elevated circulating total homocysteine (tHcy) concentrations (hyperhomocysteinemia) have been regarded as an independent risk factor for cardiovascular disease (CVD). However, several large clinical trials to correct hyperhomocysteinemia using B-vitamin supplements (particularly folic acid) have largely failed to reduce the risk of CVD. There is no doubt that a large segment of patients with CVD have hyperhomocysteinemia; therefore, it is reasonable to postulate that circulating tHcy concentrations are in part a surrogate marker for another, yet-to-be-identified risk factor(s) for CVD. We found that iron catalyzes the formation of Hcy from methionine, S-adenosylhomocysteine and cystathionine. Based on these findings, we propose that an elevated amount of non-protein-bound iron (free Fe) increases circulating tHcy. Free Fe catalyzes the formation of oxygen free radicals, and oxidized low-density lipoprotein is a well-established risk factor for vascular damage. In this review, we discuss our findings on iron-catalyzed formation of Hcy from thioethers as well as recent findings by other investigators on this issue. Collectively, these support our hypothesis that circulating tHcy is in part a surrogate marker for free Fe, which is one of the independent risk factors for CVD.
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Affiliation(s)
- Joseph E Baggott
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Tsunenobu Tamura
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Funatsu S, Kondoh T, Kawase T, Ikeda H, Nagasawa M, Denbow DM, Furuse M. Long-term consumption of dried bonito dashi (a traditional Japanese fish stock) reduces anxiety and modifies central amino acid levels in rats. Nutr Neurosci 2014; 18:256-64. [PMID: 24701973 DOI: 10.1179/1476830514y.0000000124] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Dried bonito dashi, a traditional Japanese fish stock, enhances palatability of various dishes because of its specific flavor. Daily intake of dashi has also been shown to improve mood status such as tension-anxiety in humans. This study aimed at investigating beneficial effects of dashi ingestion on anxiety/depression-like behaviors and changes in amino acid levels in the brain and plasma in rats. Male Wistar rats were given either dried bonito dashi or water for long-term (29 days; Experiment 1) or single oral administration (Experiment 2). Anxiety and depression-like behaviors were tested using the open field and forced swimming tests, respectively. Concentrations of amino acids were measured in the hippocampus, hypothalamus, cerebellum, and jugular vein. During the long-term (29 days) consumption, rats given 2% dashi frequently entered the center zone and spent more time compared with the water controls in the open field test. However, the dashi was ineffective on depression-like behavior. In the hippocampus, concentrations of hydroxyproline, anserine, and valine were increased by dashi while those of asparagine and phenylalanine were decreased. In the hypothalamus, the methionine concentration was decreased. In a single oral administration experiment, the dashi (1%, 2% or 10%) showed no effects on behaviors. Significance was observed only in the concentrations of α-aminoadipic acid, cystathionine, and ornithine in the hippocampus. Dried bonito dashi is a functional food having anxiolytic-like effects. Daily ingestion of the dashi, even at lower concentrations found in the cuisine, reduces anxiety and alters amino acid levels in the brain.
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Kraus JP, Hašek J, Kožich V, Collard R, Venezia S, Janošíková B, Wang J, Stabler SP, Allen RH, Jakobs C, Finn CT, Chien YH, Hwu WL, Hegele RA, Mudd SH. Cystathionine gamma-lyase: Clinical, metabolic, genetic, and structural studies. Mol Genet Metab 2009; 97:250-9. [PMID: 19428278 PMCID: PMC2752209 DOI: 10.1016/j.ymgme.2009.04.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 04/01/2009] [Accepted: 04/02/2009] [Indexed: 11/28/2022]
Abstract
We report studies of six individuals with marked elevations of cystathionine in plasma and/or urine. Studies of CTH, the gene that encodes cystathionine gamma-lyase, revealed the presence among these individuals of either homozygous or compound heterozygous forms of a novel large deletion, p.Gly57_Gln196del, two novel missense mutations, c.589C>T (p.Arg197Cys) and c.932C>T (p.Thr311Ile), and one previously reported alteration, c.200C>T (p.Thr67Ile). Another novel missense mutation, c.185G>T (p.Arg62His), was found in heterozygous form in three mildly hypercystathioninemic members of a Taiwanese family. In one severely hypercystathioninemic individual no CTH mutation was found. Brief clinical histories of the cystathioninemic/cystathioninuric patients are presented. Most of the novel mutations were expressed and the CTH activities of the mutant proteins determined. The crystal structure of the human enzyme, hCTH, and the evidence available as to the effects of the mutations in question, as well as those of the previously reported p.Gln240Glu, on protein structure, enzymatic activity, and responsiveness to vitamin B(6) administration are discussed. Among healthy Czech controls, 9.3% were homozygous for CTH c.1208G>T (p.Ser403Ile), previously found homozygously in 7.5% of Canadians for whom plasma total homocysteine (tHcy) had been measured. Compared to wild-type homozygotes, among the 55 Czech c.1208G>T (p.Ser403Ile) homozygotes a greater level of plasma cystathionine was found only after methionine loading. Three of the four individuals homozygous or compound heterozygous for inactivating CTH mutations had mild plasma tHcy elevations, perhaps indicating a cause-and-effect relationship. The experience with the present patients provides no evidence that severe loss of CTH activity is accompanied by adverse clinical effects.
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Affiliation(s)
- Jan P. Kraus
- Department of Pediatrics, University of Colorado School of Medicine
| | - Jindrich Hašek
- Department of Structure Analysis, Institute of Macromolecular Chemistry AS CR, Prague, Czech Republic
| | - Viktor Kožich
- Institute of Inherited Metabolic Diseases, Charles University in Prague-First Faculty of Medicine, Prague, Czech Republic
| | - Renata Collard
- Department of Pediatrics, University of Colorado School of Medicine
| | - Sarah Venezia
- Department of Pediatrics, University of Colorado School of Medicine
| | - Bohumila Janošíková
- Institute of Inherited Metabolic Diseases, Charles University in Prague-First Faculty of Medicine, Prague, Czech Republic
| | - Jian Wang
- Robarts Research Institute, London, Ontario, Canada
| | - Sally P. Stabler
- Division of Hematology, University of Colorado Health Sciences Center, Denver, CO
| | - Robert H. Allen
- Division of Hematology, University of Colorado Health Sciences Center, Denver, CO
| | - Cornelis Jakobs
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Christine T. Finn
- Massachusetts General Hospital, Department of Psychiatry, Harvard-Partners Center for Genetics and Genomics, Boston, MA
| | - Yin-Hsiu Chien
- Departments of Medical Genetics and Pediatrics, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
| | - Wuh-Liang Hwu
- Departments of Medical Genetics and Pediatrics, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
| | | | - S. Harvey Mudd
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD
- Corresponding author: S.H. Mudd (Telephone: 301-496-0681; Fax: 301-402-0245, )
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24
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Abstract
OBJECTIVE We tested whether homocysteine is formed from methionine and other thioethers in vitro and in vivo, because methionine can be chemically demethylated to homocysteine. DESIGN In in vitro studies, chemical conversions of thioethers (methionine, S-adenosylhomocysteine and cystathionine) into homocysteine were measured under various aerobic conditions. In humans, oral methionine (0.17 mmol/kg body weight) loading tests with and without an oral iron dose (ferrous sulfate, 13 mumol/kg) were performed. SETTING A university setting in Birmingham, AL, USA. SUBJECTS A total of five healthy adult subjects volunteered. RESULTS The in vitro incubation of methionine, S-adenosylhomocysteine or cystathionine with chelated iron resulted in the formation of homocysteine. These conversions were iron- and pH-dependent (pH optima between 5.0 and 6.0) and it was also chelator-dependent. In humans, oral methionine loading tests resulted in a 45% increase in the area-under-the-curve for plasma total homocysteine concentrations, when iron was given together with methionine. CONCLUSION Our data suggest that iron-dependent chemical formation of homocysteine can occur in vivo, and contribute to the plasma total homocysteine pool, since this formation can occur ceaselessly. We hypothesize that plasma total homocysteine concentrations reflect, in part, non-protein-bound iron in the body.
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Affiliation(s)
- J E Baggott
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Hullo MF, Auger S, Soutourina O, Barzu O, Yvon M, Danchin A, Martin-Verstraete I. Conversion of methionine to cysteine in Bacillus subtilis and its regulation. J Bacteriol 2006; 189:187-97. [PMID: 17056751 PMCID: PMC1797209 DOI: 10.1128/jb.01273-06] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Bacillus subtilis can use methionine as the sole sulfur source, indicating an efficient conversion of methionine to cysteine. To characterize this pathway, the enzymatic activities of CysK, YrhA and YrhB purified in Escherichia coli were tested. Both CysK and YrhA have an O-acetylserine-thiol-lyase activity, but YrhA was 75-fold less active than CysK. An atypical cystathionine beta-synthase activity using O-acetylserine and homocysteine as substrates was observed for YrhA but not for CysK. The YrhB protein had both cystathionine lyase and homocysteine gamma-lyase activities in vitro. Due to their activity, we propose that YrhA and YrhB should be renamed MccA and MccB for methionine-to-cysteine conversion. Mutants inactivated for cysK or yrhB grew similarly to the wild-type strain in the presence of methionine. In contrast, the growth of an DeltayrhA mutant or a luxS mutant, inactivated for the S-ribosyl-homocysteinase step of the S-adenosylmethionine recycling pathway, was strongly reduced with methionine, whereas a DeltayrhA DeltacysK or cysE mutant did not grow at all under the same conditions. The yrhB and yrhA genes form an operon together with yrrT, mtnN, and yrhC. The expression of the yrrT operon was repressed in the presence of sulfate or cysteine. Both purified CysK and CymR, the global repressor of cysteine metabolism, were required to observe the formation of a protein-DNA complex with the yrrT promoter region in gel-shift experiments. The addition of O-acetyl-serine prevented the formation of this protein-DNA complex.
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Affiliation(s)
- Marie-Françoise Hullo
- Unité de Génétique des Génomes Bactériens, 28 Rue du Docteur Roux, 75724 Paris Cedex 15, France
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26
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Abstract
The literature has been searched to identify evidence relating to the possible toxicity of the amino acid methionine in human subjects. Nutritional and metabolic studies have employed amounts of methionine, including the d and dl isomers, both below and above the requirement and have not reported adverse effects in adults and children. Although methionine is known to exacerbate psychopathological symptoms in schizophrenic patients, there is no evidence of similar effects in healthy subjects. The role of methionine as a precursor of homocysteine is the most notable cause for concern. A "loading dose" of methionine (0.1 g/kg) has been given, and the resultant acute increase in plasma homocysteine has been used as an index of the susceptibility to cardiovascular disease. Although this procedure results in vascular dysfunction, this is acute and unlikely to result in permanent damage. However, a 10-fold larger dose, given mistakenly, resulted in death. Longer-term studies in adults have indicated no adverse consequences of moderate fluctuations in dietary methionine intake, but intakes higher than 5 times normal resulted in elevated homocysteine levels. These effects of methionine on homocysteine and vascular function are moderated by supplements of vitamins B-6, B-12, C, and folic acid. In infants, methionine intakes of 2-5 times normal resulted in impaired growth and extremely high plasma methionine levels, but no adverse long-term consequences were observed.
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Affiliation(s)
- Peter J Garlick
- Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA.
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27
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Bar-Or D, Rael LT, Thomas GW, Kraus JP. Inhibitory Effect of Copper on Cystathionine β-Synthase Activity: Protective Effect of an Analog of the Human Albumin N-Terminus. Protein Pept Lett 2005; 12:271-3. [PMID: 15777277 DOI: 10.2174/0929866053587048] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Copper was added to truncated, recombinant cystathionine beta-synthase (CBS), and the enzyme activity was assessed by measuring the production of cystathionine. 10 microM copper significantly decreased CBS activity by 50% while 25 microM copper decreased CBS activity by 70%. This inhibition was negated when an analog of the N-terminus of human albumin, Asp-Ala-His-Lys (DAHK), a strong transition metal binding peptide, was added. The use of copper chelators could significantly reduce in vivo homocysteine levels.
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Affiliation(s)
- David Bar-Or
- Department of Trauma Research and Trauma Services, Swedish Medical Center, 501 E. Hampden Avenue, Englewood, CO 80113, USA
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28
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Aitken SM, Kirsch JF. The enzymology of cystathionine biosynthesis: strategies for the control of substrate and reaction specificity. Arch Biochem Biophys 2005; 433:166-75. [PMID: 15581575 DOI: 10.1016/j.abb.2004.08.024] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Indexed: 11/29/2022]
Abstract
The ability of enzymes to catalyze specific reactions, while excluding others, is central to cellular metabolism. Control of reaction specificity is of particular importance for enzymes that employ catalytically versatile cofactors, of which pyridoxal 5'-phosphate is a prime example. Cystathionine gamma-synthase and cystathionine beta-synthase are the first enzymes in the transsulfuration and reverse transsulfuration pathways, respectively. Each of them occupies branch-point positions in amino acid metabolism and as such are subject to transcriptional and post-translational regulation. Both enzymes catalyze the pyridoxal 5'-phosphate-dependent formation of l-cystathionine; however, their substrate and reaction specificities are distinct. The mechanisms whereby these enzymes control the chemistry of the cofactor are the subject of this review.
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Affiliation(s)
- Susan M Aitken
- Department of Biology, Carleton University, Ottawa, Ontario, Canada K1S 5B6.
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29
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James SJ, Cutler P, Melnyk S, Jernigan S, Janak L, Gaylor DW, Neubrander JA. Metabolic biomarkers of increased oxidative stress and impaired methylation capacity in children with autism. Am J Clin Nutr 2004; 80:1611-7. [PMID: 15585776 DOI: 10.1093/ajcn/80.6.1611] [Citation(s) in RCA: 576] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Autism is a complex neurodevelopmental disorder that usually presents in early childhood and that is thought to be influenced by genetic and environmental factors. Although abnormal metabolism of methionine and homocysteine has been associated with other neurologic diseases, these pathways have not been evaluated in persons with autism. OBJECTIVE The purpose of this study was to evaluate plasma concentrations of metabolites in the methionine transmethylation and transsulfuration pathways in children diagnosed with autism. DESIGN Plasma concentrations of methionine, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), adenosine, homocysteine, cystathionine, cysteine, and oxidized and reduced glutathione were measured in 20 children with autism and in 33 control children. On the basis of the abnormal metabolic profile, a targeted nutritional intervention trial with folinic acid, betaine, and methylcobalamin was initiated in a subset of the autistic children. RESULTS Relative to the control children, the children with autism had significantly lower baseline plasma concentrations of methionine, SAM, homocysteine, cystathionine, cysteine, and total glutathione and significantly higher concentrations of SAH, adenosine, and oxidized glutathione. This metabolic profile is consistent with impaired capacity for methylation (significantly lower ratio of SAM to SAH) and increased oxidative stress (significantly lower redox ratio of reduced glutathione to oxidized glutathione) in children with autism. The intervention trial was effective in normalizing the metabolic imbalance in the autistic children. CONCLUSIONS An increased vulnerability to oxidative stress and a decreased capacity for methylation may contribute to the development and clinical manifestation of autism.
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Affiliation(s)
- S Jill James
- Department of Pediatrics, University of Arkansas for Medical Sciences, and the Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA.
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30
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Ejim LJ, D'Costa VM, Elowe NH, Loredo-Osti JC, Malo D, Wright GD. Cystathionine beta-lyase is important for virulence of Salmonella enterica serovar Typhimurium. Infect Immun 2004; 72:3310-4. [PMID: 15155634 PMCID: PMC415680 DOI: 10.1128/iai.72.6.3310-3314.2004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The biosynthesis of methionine in bacteria requires the mobilization of sulfur from Cys by the formation and degradation of cystathionine. Cystathionine beta-lyase, encoded by metC in bacteria and STR3 in Schizosaccharomyces pombe, catalyzes the breakdown of cystathionine to homocysteine, the penultimate step in methionine biosynthesis. This enzyme has been suggested to be the target for pyridinamine antimicrobial agents. We have demonstrated, by using purified enzymes from bacteria and yeast, that cystathionine beta-lyase is not the likely target of these agents. Nonetheless, an insertional inactivation of metC in Salmonella enterica serovar Typhimurium resulted in the attenuation of virulence in a mouse model of systemic infection. This result confirms a previous chemical validation of the Met biosynthetic pathway as a target for the development of antibacterial agents and demonstrates that cystathionine beta-lyase is important for bacterial virulence.
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Affiliation(s)
- Linda J Ejim
- Antimicrobial Research Centre, Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada L8N 3Z5
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31
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Abstract
Building on the work of Martinov et al. (2000), a mathematical model is developed for the methionine cycle. A large amount of information is available about the enzymes that catalyse individual reaction steps in the cycle, from methionine to S-adenosylmethionine to S-adenosylhomocysteine to homocysteine, and the removal of mass from the cycle by the conversion of homocysteine to cystathionine. Nevertheless, the behavior of the cycle is very complicated since many substrates alter the activities of the enzymes in the reactions that produce them, and some can also alter the activities of other enzymes in the cycle. The model consists of four differential equations, based on known reaction kinetics, that can be solved to give the time course of the concentrations of the four main substrates in the cycle under various circumstances. We show that the behavior of the model in response to genetic abnormalities and dietary deficiencies is similar to the changes seen in a wide variety of experimental studies. We conduct computational "experiments" that give understanding of the regulatory behavior of the methionine cycle under normal conditions and the behavior in the presence of genetic variation and dietary deficiencies.
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Affiliation(s)
- Michael C Reed
- Department of Mathematics, Duke University, Durham, NC 27708, USA.
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32
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Panayiotidis MI, Stabler SP, Allen RH, Ahmad A, White CW. Cigarette smoke extract increases S-adenosylmethionine and cystathionine in human lung epithelial-like (A549) cells. Chem Biol Interact 2004; 147:87-97. [PMID: 14726155 DOI: 10.1016/j.cbi.2003.10.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The effect of cigarette smoke extract (CSE) on S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and sulfur amino acid metabolism was examined in human lung epithelial-like (A549) cells exposed to various CSE concentrations (2.5-100%) for 24 or 48 h. Intracellular SAM and SAM/SAH ratio were elevated after exposure to CSE for 48 h. Cell SAH content decreased, but the effect was not consistent. Cellular cystathionine, cysteine, and methionine levels were increased after CSE exposure for 48h. Sub-acute exposure to CSE induced increases in cellular SAM and SAM/SAH ratio. The transsulfuration pathway was likely activated by CSE since cystathionine increased, potentially contributing to the increased total intracellular GSH content.
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Affiliation(s)
- Mihalis I Panayiotidis
- Department of Pediatrics, National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206, USA
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33
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Abstract
The pathway for the biosynthesis of cysteine and homocysteine in Methanococcus jannaschii has been examined using a gas chromatography-mass spectrometry (GC-MS) stable isotope dilution method to identify and quantitate the intermediates in the pathways. The first step in the pathway, and the one responsible for incorporation of sulfur into both cysteine and methionine, is the reaction between O-phosphohomoserine and a presently unidentified sulfur source present in cell extracts, to produce L-homocysteine. This sulfur source was shown not to be sulfide. The resulting L-homocysteine then reacts with O-phosphoserine to form L-cystathionine, which is cleaved to L-cysteine. The pathway has elements of both the plant and mammalian pathways in that the sulfur is first incorporated into homocysteine using O-phosphohomoserine as the acceptor and the resulting homocysteine, via transsulfuration, supplies the sulfur for cysteine formation. The pathway leading to these two amino acids represents an example of metabolic thrift where the preexisting cellular metabolites O-phosphohomoserine and O-phosphoserine are used as the ultimate source of the carbon framework for the biosynthesis of these amino acids. These findings explain the absence of identifiable genes in the genome of this organism for the biosynthesis of cysteine and homocysteine.
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Affiliation(s)
- Robert H White
- Department of Biochemistry, Virginia Polytechnic Institute and State University, 103 Engel Hall (0308) Blacksburg, VA 24061-0308, USA.
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34
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Lee HS, Hwang BJ. Methionine biosynthesis and its regulation in Corynebacterium glutamicum: parallel pathways of transsulfuration and direct sulfhydrylation. Appl Microbiol Biotechnol 2003; 62:459-67. [PMID: 12845493 DOI: 10.1007/s00253-003-1306-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2002] [Revised: 03/04/2003] [Accepted: 03/06/2003] [Indexed: 10/26/2022]
Abstract
There are two alternative pathways leading to methionine synthesis in microorganisms: The transsulfuration pathway involves cystathionine as the intermediate and utilizes cysteine as the sulfur source, but the direct sulfhydrylation pathway bypasses cystathionine and uses inorganic sulfur instead. While most microorganisms synthesize methionine via either one of these pathways, Corynebacterium glutamicum utilizes both pathways, which appear to be fully functional. In C. glutamicum, each pathway is catalyzed by independent enzymes and is tightly regulated by methionine. Although the physiological significance of parallel pathways remains to be elucidated, their presence suggests metabolic flexibility and efficient adaptation of the organism to its environment.
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Affiliation(s)
- H-S Lee
- Department of Biotechnology, Korea University, Jochiwon, Choongnam 339-700, Korea.
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35
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Abstract
Alterations of hepatic glutathione level by betaine were observed previously. In this study effects of betaine administration (1000 mg/kg, i.p.) on S-amino acid metabolism in rats and mice were investigated. Hepatic glutathione level decreased rapidly followed by marked elevation in 24 hr. Concentrations of S-adenosylmethionine, S-adenosylhomocysteine, and methionine were increased whereas cystathionine decreased significantly, suggesting that homocysteine generated in the methionine cycle is preferentially remethylated to methionine rather than being utilized for synthesis of cysteine. Hepatic cysteine concentration declined immediately, but plasma cysteine increased. Effect of betaine on hepatic cysteine uptake was estimated from the difference in cysteine concentration in major blood vessels connected to liver. Cysteine concentration either in the portal vein or abdominal aorta was not altered, however, a significant increase was noted in the hepatic vein, indicating that hepatic uptake of cysteine was decreased by betaine treatment. Activities of glutamate cysteine ligase, cystathionine beta-synthase, and cystathionine gamma-lyase were elevated in 24 hr. Pretreatment with propargylglycine, an irreversible inhibitor of cystathionine gamma-lyase, did not abolish the betaine-induced reduction of hepatic glutathione in 4 hr, however, the elevation at t=24 hr was blocked completely. In conclusion the present results indicate that betaine administration induces time-dependent changes on hepatic metabolism of S-amino acids. Betaine enhances metabolic reactions in the methionine cycle, but inhibits cystathionine synthesis and cysteine uptake, leading to a decrease in supply of cysteine for glutathione synthesis. Reduction in glutathione is subsequently reversed due to induction of cysteine synthesis and glutamate cysteine ligase activity.
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Affiliation(s)
- Sang K Kim
- College of Pharmacy, Seoul National University, San 56-1 Shinrim-Dong, Kwanak-Ku, Seoul, South Korea
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37
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Abstract
An O-acetylserine sulfhydrylase (OASS) from the hyperthermophilic archaeon Aeropyrum pernix K1, which shares the pyridoxal 5'-phosphate binding motif with both OASS and cystathionine beta-synthase (CBS), was cloned and expressed by using Escherichia coli Rosetta(DE3). The purified protein was a dimer and contained pyridoxal 5'-phosphate. It was shown to be an enzyme with CBS activity as well as OASS activity in vitro. The enzyme retained 90% of its activity after a 6-h incubation at 100 degrees C. In the O-acetyl-L-serine sulfhydrylation reaction, it had a pH optimum of 6.7, apparent K(m) values for O-acetyl-L-serine and sulfide of 28 and below 0.2 mM, respectively, and a rate constant of 202 s(-1). In the L-cystathionine synthetic reaction, it showed a broad pH optimum in the range of 8.1 to 8.8, apparent K(m) values for L-serine and L-homocysteine of 8 and 0.51 mM, respectively, and a rate constant of 0.7 s(-1). A. pernix OASS has a high activity in the L-cysteine desulfurization reaction, which produces sulfide and S-(2,3-hydroxy-4-thiobutyl)-L-cysteine from L-cysteine and dithiothreitol.
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Affiliation(s)
- Koshiki Mino
- Special Division for Human Life Technology, National Institute of Advanced Industrial Science and Technology (AIST, Kansai), Ikeda, Osaka 563-8577, Japan
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38
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Abstract
betaC-S Lyase catalyzes the alpha,beta-elimination of L-cysteine to hydrogen sulfide, which is one of the main causes of oral malodor and is highly toxic to mammalian cells. We evaluated the capacity of six species of oral streptococci to produce hydrogen sulfide. The crude enzyme extract from Streptococcus anginosus had the greatest capacity. However, comparative analysis of amino acid sequences did not detect any meaningful differences in the S. anginosus betaC-S lyase. The capacity of S. anginosus purified betaC-S lyase to degrade L-cysteine was also extremely high, while its capacity to degrade L-cystathionine was unremarkable. These findings suggest that the extremely high capacity of S. anginosus to produce hydrogen sulfide is due to the unique characteristic of betaC-S lyase from that organism.
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Affiliation(s)
- Yasuo Yoshida
- Department of Preventive Dentistry, Kyushu University, Faculty of Dental Science, Fukuoka 812-8582, Japan
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De Angelis M, Curtin AC, McSweeney PLH, Faccia M, Gobbetti M. Lactobacillus reuteri DSM 20016: purification and characterization of a cystathionine gamma-lyase and use as adjunct starter in cheesemaking. J DAIRY RES 2002; 69:255-67. [PMID: 12222803 DOI: 10.1017/s0022029902005514] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A homo-tetrameric approximately 160-kDa cystathionine gamma-lyase was purified to homogeneity from Lactobacillus reuteri DSM 20016 by four chromatographic steps. The activity was pyridoxal-5'-phosphate dependent and the enzyme catalyzed the alpha,gamma-elimination reaction of L-cystathionine, producing L-cysteine, ammonia and alpha-ketobutyrate. The enzyme was active towards a range of amino acids and amino acid derivatives, including methionine. The pH and temperature optima were found to be 8.0 and 35 degrees C. respectively. Isoelectric pH (pI) was approximately 5.0 as determined by two-dimensional electrophoresis. Sensitivity to chemical inhibitors was typical of lactococcal cystathionine gamma- and beta-lyases, except it was inhibited by sulphydryl reagents. The N-terminal sequence was MKFNTQLIHGGNSED, which had 100% homology with cystathionine beta-lyase of Lb. reuteri 104R (Accession Number (CAC05298). Lb. reuteri DSM 20016. together with 10 other strains of non-starter lactic acid bacteria, was used as adjunct starter in the production of miniature ('anestrato Pugliese-like cheeses. After 40 d ripening, the water-soluble extract of the cheeses with added Lactobacillus fermentum DT41 and Lb. reuteri DSM 20016 contained the highest enzyme activities on cystathionine and methionine substrates. Determinations of methanethiol, dimethyl sulphide, dimethyl disulphide and dimethyl trisulphide in the miniature cheeses confirmed the findings of enzyme activities.
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Affiliation(s)
- Maria De Angelis
- Dipartimento di Scienze degli Alimenti, Università degli Studi di Perugia, Italy
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40
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Dierickx PJ, De Beer JO, Scheers EM. Cystathionine pathway-dependent cytotoxicities of diethyl maleate and diamide in rat and human hepatoma-derived cell cultures. Altern Lab Anim 2002; 30:61-8. [PMID: 11827570 DOI: 10.1177/026119290203000106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glutathione (GSH) plays a role in many toxicologically important metabolic processes. It was previously established that L-buthionine S,R-sulphoximine (BSO), a specific inhibitor of (- glutamylcysteine synthetase, reduces the GSH content more efficiently in rat (Fa32) than in human (HEp-G2) hepatoma-derived cells. We therefore investigated whether the cystathionase inhibitor propargylglycine (PPG) could further decrease the BSO-induced GSH depletion in HEp-G2 cells. The influence of the cystathionine precursors N-acetylmethionine, methionine and homocysteine on the cytotoxicity of diethyl maleate (DEM) and diamide [1,1'-azobis(N,N-dimethylformamide)] was also investigated. PPG reduced the GSH content in both cell lines. A further GSH decrease in HEp-G2 was obtained when using a BSO + PPG combination containing relatively high concentrations of PPG. BSO diminished the toxicity of PPG. Homocysteine was the most efficacious of the tested cystathionine precursors in increasing the GSH content and reducing the cytotoxicity of DEM and diamide in Fa32 and HEp-G2 cells.
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Affiliation(s)
- Paul J Dierickx
- Laboratorium Biochemische Toxikologie, Instituut voor Volksgezondheid, Afdeling Toxikologie, Wytsmanstraat 14, 1050 Brussels, Belgium
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Abstract
OBJECTIVE To validate an automated chemiluminescent immunoassay for measuring serum cobalamin concentration in cats, to establish and validate gas chromatography-mass spectrometry techniques for use in quantification of methylmalonic acid, homocysteine, cysteine, cystathionine, and methionine in sera from cats, and to investigate serum concentrations of methylmalonic acid, methionine, homocysteine, cystathionine, and cysteine as indicators of biochemical abnormalities accompanying severe cobalamin (vitamin B12) deficiency in cats. SAMPLE POPULATION Serum samples of 40 cats with severe cobalamin deficiency (serum cobalamin concentration < 100 ng/L) and 24 control cats with serum cobalamin concentration within the reference range. PROCEDURE Serum concentrations of cobalamin were measured, using a commercial automated chemiluminescent immunoassay. Serum concentrations of methylmalonic acid, methionine, homocysteine, cystathionine, and cysteine were measured, using gas chromatography-mass spectrometry, selected ion monitoring, stable-isotope dilution assays. RESULTS Cats with cobalamin deficiency had significant increases in mean serum concentrations bf methylmalonic acid (9,607 nmol/L), compared with healthy cats (448 nmol/L). Affected cats also had substantial disturbances in amino acid metabolism, compared with healthy cats, with significantly increased serum concentrations of methionine (133.8 vs 101.1 micromol/L) and significantly decreased serum concentrations of cystathionine (449.6 vs 573.2 nmol/L) and cysteine (142.3 vs 163.9 micromol/L). There was not a significant difference in serum concentrations of homocysteine between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE Cats with gastrointestinal tract disease may have abnormalities in amino acid metabolism consistent with cobalamin deficiency. Parenteral administration of cobalamin may be necessary to correct these biochemical abnormalities.
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Affiliation(s)
- C G Ruaux
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station 77843-4474, USA
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42
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Chambers JC, Ueland PM, Wright M, Doré CJ, Refsum H, Kooner JS. Investigation of relationship between reduced, oxidized, and protein-bound homocysteine and vascular endothelial function in healthy human subjects. Circ Res 2001; 89:187-92. [PMID: 11463727 DOI: 10.1161/hh1401.093459] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previous studies investigating homocysteine and vascular disease have relied on total plasma homocysteine as the sole index of homocysteine status. We examined the dynamic relationship between vascular endothelial function and concentrations of total, protein-bound oxidized, free oxidized, and reduced homocysteine to identify the homocysteine form associated with endothelial dysfunction in humans. We investigated 14 healthy volunteers (10 men, 4 women). Brachial artery flow-mediated dilatation was measured at baseline and at 30, 60, 120, 240, and 360 minutes after oral (1) L-methionine (50 mg/kg), (2) L-homocysteine (5 mg/kg), and (3) placebo. Plasma concentrations of total, protein-bound oxidized, free oxidized, and reduced homocysteine were measured at each time point, and nitroglycerin-induced dilatation at was assessed at 0, 120, and 360 minutes. Flow-mediated dilatation fell, and concentrations of total, protein-bound oxidized, free oxidized, and reduced homocysteine increased after oral homocysteine and oral methionine (all P<0.05 for difference in time course compared with placebo). Flow-mediated dilatation showed a reciprocal relationship with reduced homocysteine during both homocysteine and methionine loading. In both loading studies, peak reduction in flow-mediated dilatation coincided with maximal reduced homocysteine concentrations. In contrast, there was no consistent relationship between flow-mediated dilatation and free oxidized homocysteine, protein-bound oxidized homocysteine, or related species. Nitroglycerin-induced dilatation was unchanged by oral homocysteine and oral methionine (P>0.10 compared with placebo). Reduced homocysteine is closely associated with endothelial dysfunction during oral methionine and oral homocysteine loading. Our observations support the hypothesis that reduced homocysteine is the deleterious form of homocysteine for vascular function in vivo and suggest a less important role for other homocysteine species.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Department of Medical Statistics and Evaluation, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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43
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Pogribna M, Melnyk S, Pogribny I, Chango A, Yi P, James SJ. Homocysteine metabolism in children with Down syndrome: in vitro modulation. Am J Hum Genet 2001; 69:88-95. [PMID: 11391481 PMCID: PMC1226051 DOI: 10.1086/321262] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2001] [Accepted: 04/16/2001] [Indexed: 11/03/2022] Open
Abstract
The gene for cystathionine beta-synthase (CBS) is located on chromosome 21 and is overexpressed in children with Down syndrome (DS), or trisomy 21. The dual purpose of the present study was to evaluate the impact of overexpression of the CBS gene on homocysteine metabolism in children with DS and to determine whether the supplementation of trisomy 21 lymphoblasts in vitro with selected nutrients would shift the genetically induced metabolic imbalance. Plasma samples were obtained from 42 children with karyotypically confirmed full trisomy 21 and from 36 normal siblings (mean age 7.4 years). Metabolites involved in homocysteine metabolism were measured and compared to those of normal siblings used as controls. Lymphocyte DNA methylation status was determined as a functional endpoint. The results indicated that plasma levels of homocysteine, methionine, S-adenosylhomocysteine, and S-adenosylmethionine were all significantly decreased in children with DS and that their lymphocyte DNA was hypermethylated relative to that in normal siblings. Plasma levels of cystathionine and cysteine were significantly increased, consistent with an increase in CBS activity. Plasma glutathione levels were significantly reduced in the children with DS and may reflect an increase in oxidative stress due to the overexpression of the superoxide dismutase gene, also located on chromosome 21. The addition of methionine, folinic acid, methyl-B(12), thymidine, or dimethylglycine to the cultured trisomy 21 lymphoblastoid cells improved the metabolic profile in vitro. The increased activity of CBS in children with DS significantly alters homocysteine metabolism such that the folate-dependent resynthesis of methionine is compromised. The decreased availability of homocysteine promotes the well-established "folate trap," creating a functional folate deficiency that may contribute to the metabolic pathology of this complex genetic disorder.
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Affiliation(s)
- Marta Pogribna
- Division of Biochemical Toxicology, Food and Drug Administration National Center for Toxicological Research, Jefferson, AR; and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock
| | - Stepan Melnyk
- Division of Biochemical Toxicology, Food and Drug Administration National Center for Toxicological Research, Jefferson, AR; and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock
| | - Igor Pogribny
- Division of Biochemical Toxicology, Food and Drug Administration National Center for Toxicological Research, Jefferson, AR; and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock
| | - Abalo Chango
- Division of Biochemical Toxicology, Food and Drug Administration National Center for Toxicological Research, Jefferson, AR; and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock
| | - Ping Yi
- Division of Biochemical Toxicology, Food and Drug Administration National Center for Toxicological Research, Jefferson, AR; and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock
| | - S. Jill James
- Division of Biochemical Toxicology, Food and Drug Administration National Center for Toxicological Research, Jefferson, AR; and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock
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44
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Abstract
Methionine metabolism forms homocysteine via transmethylation. Homocysteine is either 1) condensed to form cystathionine, which is cleaved to form cysteine, or 2) remethylated back to methionine. Measuring this cycle with the use of isotopically labeled methionine tracers is problematic, because the tracer is infused into and measured from blood, whereas methionine metabolism occurs inside cells. Because plasma homocysteine and cystathionine arise from intracellular metabolism of methionine, plasma homocysteine and cystathionine enrichments can be used to define intracellular methionine enrichment during an infusion of labeled methionine. Eight healthy, postabsorptive volunteers were given a primed continuous infusion of [1-13C]methionine and [methyl-2H(3)]methionine for 8 h. Enrichments in plasma methionine, [13C]homocysteine and [13C]cystathionine were measured. In contrast to plasma methionine enrichments, the plasma [13C]homocysteine and [13C]cystathionine enrichments rose to plateau slowly (rate constant: 0.40 +/- 0.03 and 0.49 +/- 0.09 h(-1), respectively). The enrichment ratios of plasma [13C]homocysteine to [13C]methionine and [13C]cystathionine to [13C]methionine were 58 +/- 3 and 54 +/- 3%, respectively, demonstrating a large intracellular/extracellular partitioning of methionine. These values were used to correct methionine kinetics. The corrections increase previously reported rates of methionine kinetics by approximately 40%.
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Affiliation(s)
- M J MacCoss
- Departments of Medicine and Chemistry, University of Vermont, Burlington, Vermont 05405, USA
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45
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Or-Rashid MM, Onodera R, Wadud S. Biosynthesis of methionine from homocysteine, cystathionine and homoserine plus cysteine by mixed rumen microorganisms in vitro. Appl Microbiol Biotechnol 2001; 55:758-64. [PMID: 11525625 DOI: 10.1007/s002530100548] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study quantitatively investigated the biosynthesis of methionine (Met) and the production of related compounds from homocysteine (Hcys), cystathionine (Cysta), and homoserine (Hser) plus cysteine (Cys) by rumen bacteria (B) or protozoa (P) alone and by a mixture of these bacteria and protozoa (BP). Rumen contents were collected from fistulated goats to prepare the microbial suspensions and were anaerobically incubated at 39 degrees C for 12 h. Hcys, Cysta, and Hser plus Cys were catabolized by all rumen microbial fractions to different extents. B, P, and BP converted Hcys to Met with 2-aminobutyric acid (2AB) and methionine sulfoxide. The Met-producing ability of B (83.2 micromol g(-1) microbial nitrogen; MN) from Hcys was about 3.6 times higher than that of P in a 6-h incubation period. The ability of BP, during the same incubation period, was about 30.0% higher than that of B. Hcys, Met, and 2AB were formed when Cysta was incubated with B, P, or BP. Rumen microbial fermentation of Hser plus Cys led to the formation of Cysta, Met (through Hcys), and 2AB. Thus the results indicated that a trans-sulfurylation pathway for Met synthesis was operating in the rumen bacteria and protozoa. The results mentioned above have been demonstrated for the first time in B, P, and BP in the present study.
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Affiliation(s)
- M M Or-Rashid
- Division of Animal Science, Miyazaki University, Japan.
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46
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Abstract
Two intersecting pathways, the methionine cycle and the transsulfuration sequence, compose the mechanisms for homocysteine metabolism in mammals. The methionine cycle occurs in all tissues and provides for the remethylation of homocysteine, which conserves methionine. In addition, the cycle is essential for the recycling of methyltetrahydrofolate. The synthesis of cystathionine is the first reaction in the irreversible pathway for the catabolism of homocysteine by means of the sequential conversion to cysteine and sulfate. This pathway has a limited distribution and is found primarily in the liver, kidney, small intestine and pancreas. Regulation of homocysteine metabolism is achieved by changes in the quantity of homocysteine distributed between the two competing pathways. Two mechanisms are basic to the regulatory process. Changes in tissue content of the relevant enzymes are the response to sustained perturbations. The inherent kinetic properties of the enzymes provide an immediate response to alterations in the tissue concentrations of substrates and other metabolic effectors. S-adenosylmethionine, S-adenosylhomocysteine, and methyltetrahydrofolate are of particular importance in that context.
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Affiliation(s)
- J D Finkelstein
- Department of Veteran Affairs Medical Center and George Washington University, Washington, DC 20422, USA.
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47
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Yamagata S, Ichioka K, Goto K, Mizuno Y, Iwama T. Occurrence of transsulfuration in synthesis of L-homocysteine in an extremely thermophilic bacterium, Thermus thermophilus HB8. J Bacteriol 2001; 183:2086-92. [PMID: 11222609 PMCID: PMC95106 DOI: 10.1128/jb.183.6.2086-2092.2001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A cell extract of an extremely thermophilic bacterium, Thermus thermophilus HB8, cultured in a synthetic medium catalyzed cystathionine gamma-synthesis with O-acetyl-L-homoserine and L-cysteine as substrates but not beta-synthesis with DL-homocysteine and L-serine (or O-acetyl-L-serine). The amounts of synthesized enzymes metabolizing sulfur-containing amino acids were estimated by determining their catalytic activities in cell extracts. The syntheses of cystathionine beta-lyase (EC 4.4.1.8) and O-acetyl-L-serine sulfhydrylase (EC 4.2.99.8) were markedly repressed by L-methionine supplemented to the medium. L-Cysteine and glutathione, both at 0.5 mM, added to the medium as the sole sulfur source repressed the synthesis of O-acetylserine sulfhydrylase by 55 and 73%, respectively, confirming that this enzyme functions as a cysteine synthase. Methionine employed at 1 to 5 mM in the same way derepressed the synthesis of O-acetylserine sulfhydrylase 2.1- to 2.5-fold. A method for assaying a low concentration of sulfide (0.01 to 0.05 mM) liberated from homocysteine by determining cysteine synthesized with it in the presence of excess amounts of O-acetylserine and a purified preparation of the sulfhydrylase was established. The extract of cells catalyzed the homocysteine gamma-lyase reaction, with a specific activity of 5 to 7 nmol/min/mg of protein, but not the methionine gamma-lyase reaction. These results suggested that cysteine was also synthesized under the conditions employed by the catalysis of O-acetylserine sulfhydrylase using sulfur of homocysteine derived from methionine. Methionine inhibited O-acetylserine sulfhydrylase markedly. The effects of sulfur sources added to the medium on the synthesis of O-acetylhomoserine sulfhydrylase and the inhibition of the enzyme activity by methionine were mostly understood by assuming that the organism has two proteins having O-acetylhomoserine sulfhydrylase activity, one of which is cystathionine gamma-synthase. Although it has been reported that homocysteine is directly synthesized in T. thermophilus HB27 by the catalysis of O-acetylhomoserine sulfhydrylase on the basis of genetic studies (T. Kosuge, D. Gao, and T. Hoshino, J. Biosci. Bioeng. 90:271-279, 2000), the results obtained in this study for the behaviors of related enzymes indicate that sulfur is first incorporated into cysteine and then transferred to homocysteine via cystathionine in T. thermophilus HB8.
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Affiliation(s)
- S Yamagata
- Department of Biotechnology, Faculty of Agriculture, Gifu University, Gifu 501-1193, Japan
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48
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Abstract
In the enteric bacteria Escherichia coli and Salmonella enterica, sulfate is reduced to sulfide and assimilated into the amino acid cysteine; in turn, cysteine provides the sulfur atom for other sulfur-bearing molecules in the cell, including methionine. These organisms cannot use methionine as a sole source of sulfur. Here we report that this constraint is not shared by many other enteric bacteria, which can use either cysteine or methionine as the sole source of sulfur. The enteric bacterium Klebsiella aerogenes appears to use at least two pathways to allow the reduced sulfur of methionine to be recycled into cysteine. In addition, the ability to recycle methionine on solid media, where cys mutants cannot use methionine as a sulfur source, appears to be different from that in liquid media, where they can. One pathway likely uses a cystathionine intermediate to convert homocysteine to cysteine and is induced under conditions of sulfur starvation, which is likely sensed by low levels of the sulfate reduction intermediate adenosine-5'-phosphosulfate. The CysB regulatory proteins appear to control activation of this pathway. A second pathway may use a methanesulfonate intermediate to convert methionine-derived methanethiol to sulfite. While the transsulfurylation pathway may be directed to recovery of methionine, the methanethiol pathway likely represents a general salvage mechanism for recovery of alkane sulfide and alkane sulfonates. Therefore, the relatively distinct biosyntheses of cysteine and methionine in E. coli and Salmonella appear to be more intertwined in Klebsiella.
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Affiliation(s)
- T A Seiflein
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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49
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Whanger PD, Ip C, Polan CE, Uden PC, Welbaum G. Tumorigenesis, metabolism, speciation, bioavailability, and tissue deposition of selenium in selenium-enriched ramps (Allium tricoccum). J Agric Food Chem 2000; 48:5723-5730. [PMID: 11087545 DOI: 10.1021/jf000739s] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ramps (Allium tricoccum) were grown either in a mixture of vermiculite and peat moss or hydroponically with various concentrations of selenium as sodium selenate. The concentrations used were from 30 to 300 mg of selenium/kg of vermiculite-peat moss or from 10 to 120 mg/L in the hydroponic solutions. Levels as high as 784 mg of selenium/kg were obtained in the ramp bulbs when grown with high levels of selenium in the vermiculite-peat moss, and up to 600 mg of selenium/kg was obtained hydroponically. The predominant form of selenium in the ramp bulbs at all concentrations of selenium was Se-methylselenocysteine, with lower amounts of selenate, Se-cystathionine, and glutamyl-Se-methylselenocysteine. There was a approximately 43% reduction in chemically induced mammary tumors when rats were fed a diet with Se-enriched ramps. Dietary Se-enriched ramps for rats did not result in excessive tissue selenium accumulation or undesirable side effects. Bioavailability studies with rats indicated that selenium in ramps was 15-28% more available for regeneration of glutathione peroxidase activity than inorganic selenium as selenite. Therefore, Se-enriched ramps appear to have potential for the reduction of cancer in humans.
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Affiliation(s)
- P D Whanger
- Department of Horticulture, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
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50
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Mosharov E, Cranford MR, Banerjee R. The quantitatively important relationship between homocysteine metabolism and glutathione synthesis by the transsulfuration pathway and its regulation by redox changes. Biochemistry 2000; 39:13005-11. [PMID: 11041866 DOI: 10.1021/bi001088w] [Citation(s) in RCA: 375] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Homocysteine is a key junction metabolite in methionine metabolism. It suffers two major metabolic fates: transmethylation catalyzed by methionine synthase or betaine homocysteine methyl transferase and transsulfuration catalyzed by cystathionine beta-synthase leading to cystathionine. The latter is subsequently converted to cysteine, a precursor of glutathione. Studies with purified mammalian methionine synthase and cystathionine beta-synthase have revealed the oxidative sensitivity of both junction enzymes, suggesting the hypothesis that redox regulation of this pathway may be physiologically significant. This hypothesis has been tested in a human hepatoma cell line in culture in which the flux of homocysteine through transsulfuration under normoxic and oxidative conditions has been examined. Addition of 100 microM H(2)O(2) or tertiary butyl hydroperoxide increased cystathionine production 1.6- and 2.1-fold from 82 +/- 7 micromol h(-)(1) (L of cells)(-)(1) to 136 +/- 15 and 172 +/- 23 micromol h(-)(1) (L of cells)(-)(1), respectively. The increase in homocysteine flux through the transsulfuration pathway exhibited a linear dose dependence on the concentrations of both oxidants (50-200 microM H(2)O(2) and 10-200 microM tertiary butyl hydroperoxide). Furthermore, our results reveal that approximately half of the intracellular glutathione pool in human liver cells is derived from homocysteine via the transsulfuration pathway. The redox sensitivity of the transsulfuration pathway can be rationalized as an autocorrective response that leads to an increased level of glutathione synthesis in cells challenged by oxidative stress. In summary, this study demonstrates the importance of the homocysteine-dependent transsulfuration pathway in the maintenance of the intracellular glutathione pool, and the regulation of this pathway under oxidative stress conditions. Aberrations in this pathway could compromise the redox buffering capacity of cells, which may in turn be related to the pathophysiology of the different homocysteine-related diseases.
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Affiliation(s)
- E Mosharov
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664, USA
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