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Cudalbu C, Cooper AJL. Editorial for the special issue on Brain Biochemistry in Liver Disease. Anal Biochem 2023; 677:115248. [PMID: 37453580 DOI: 10.1016/j.ab.2023.115248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Affiliation(s)
- Cristina Cudalbu
- CIBM Center for Biomedical Imaging, Switzerland; Animal Imaging and Technology (AIT), EPFL, Lausanne, Switzerland.
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, USA; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
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Cooper AJL, Dorai T, Pinto JT, Denton TT. Metabolic Heterogeneity, Plasticity, and Adaptation to "Glutamine Addiction" in Cancer Cells: The Role of Glutaminase and the GTωA [Glutamine Transaminase-ω-Amidase (Glutaminase II)] Pathway. Biology (Basel) 2023; 12:1131. [PMID: 37627015 PMCID: PMC10452834 DOI: 10.3390/biology12081131] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/06/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023]
Abstract
Many cancers utilize l-glutamine as a major energy source. Often cited in the literature as "l-glutamine addiction", this well-characterized pathway involves hydrolysis of l-glutamine by a glutaminase to l-glutamate, followed by oxidative deamination, or transamination, to α-ketoglutarate, which enters the tricarboxylic acid cycle. However, mammalian tissues/cancers possess a rarely mentioned, alternative pathway (the glutaminase II pathway): l-glutamine is transaminated to α-ketoglutaramate (KGM), followed by ω-amidase (ωA)-catalyzed hydrolysis of KGM to α-ketoglutarate. The name glutaminase II may be confused with the glutaminase 2 (GLS2) isozyme. Thus, we recently renamed the glutaminase II pathway the "glutamine transaminase-ω-amidase (GTωA)" pathway. Herein, we summarize the metabolic importance of the GTωA pathway, including its role in closing the methionine salvage pathway, and as a source of anaplerotic α-ketoglutarate. An advantage of the GTωA pathway is that there is no net change in redox status, permitting α-ketoglutarate production during hypoxia, diminishing cellular energy demands. We suggest that the ability to coordinate control of both pathways bestows a metabolic advantage to cancer cells. Finally, we discuss possible benefits of GTωA pathway inhibitors, not only as aids to studying the normal biological roles of the pathway but also as possible useful anticancer agents.
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Affiliation(s)
- Arthur J. L. Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA; (T.D.); (J.T.P.)
| | - Thambi Dorai
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA; (T.D.); (J.T.P.)
- Department of Urology, New York Medical College, Valhalla, NY 10595, USA
| | - John T. Pinto
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA; (T.D.); (J.T.P.)
| | - Travis T. Denton
- Department Pharmaceutical Sciences, College of Pharmacy & Pharmaceutical Sciences, Washington State University Health Sciences Spokane, Spokane, WA 99202, USA
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University Health Sciences Spokane, Spokane, WA 99164, USA
- Steve Gleason Institute for Neuroscience, Washington State University Health Sciences Spokane, Spokane, WA 99164, USA
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Jeitner TM, Azcona JA, Ables GP, Cooke D, Horowitz MC, Singh P, Kelly JM, Cooper AJL. Cystine rather than cysteine is the preferred substrate for β-elimination by cystathionine γ-lyase: implications for dietary methionine restriction. GeroScience 2023:10.1007/s11357-023-00788-4. [PMID: 37217633 DOI: 10.1007/s11357-023-00788-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 03/31/2023] [Indexed: 05/24/2023] Open
Abstract
Dietary methionine restriction (MR) increases longevity by improving health. In experimental models, MR is accompanied by decreased cystathionine β-synthase activity and increased cystathionine γ-lyase activity. These enzymes are parts of the transsulfuration pathway which produces cysteine and 2-oxobutanoate. Thus, the decrease in cystathionine β-synthase activity is likely to account for the loss of tissue cysteine observed in MR animals. Despite this decrease in cysteine levels, these tissues exhibit increased H2S production which is thought to be generated by β-elimination of the thiol moiety of cysteine, as catalyzed by cystathionine β-synthase or cystathionine γ-lyase. Another possibility for this H2S production is the cystathionine γ-lyase-catalyzed β-elimination of cysteine persulfide from cystine, which upon reduction yields H2S and cysteine. Here, we demonstrate that MR increases cystathionine γ-lyase production and activities in the liver and kidneys, and that cystine is a superior substrate for cystathionine γ-lyase catalyzed β-elimination as compared to cysteine. Moreover, cystine and cystathionine exhibit comparable Kcat/Km values (6000 M-1 s-1) as substrates for cystathionine γ-lyase-catalyzed β-elimination. By contrast, cysteine inhibits cystathionine γ-lyase in a non-competitive manner (Ki ~ 0.5 mM), which limits its ability to function as a substrate for β-elimination by this enzyme. Cysteine inhibits the enzyme by reacting with its pyridoxal 5'-phosphate cofactor to form a thiazolidine and in so doing prevents further catalysis. These enzymological observations are consistent with the notion that during MR cystathionine γ-lyase is repurposed to catabolize cystine and thereby form cysteine persulfide, which upon reduction produces cysteine.
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Affiliation(s)
- Thomas M Jeitner
- Department of Radiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA.
| | - Juan A Azcona
- Department of Radiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA
| | - Gene P Ables
- Orentreich Foundation for the Advancement of Science, Inc, 855 Route 301, Cold Spring, NY, 10516, USA
| | - Diana Cooke
- Orentreich Foundation for the Advancement of Science, Inc, 855 Route 301, Cold Spring, NY, 10516, USA
| | - Mark C Horowitz
- Department of Orthopedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Pradeep Singh
- Department of Radiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - James M Kelly
- Department of Radiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Citigroup Biomedical Imaging Center, Weill Cornell Medicine, 516 East 72Nd St, New York, NY, 10021, USA
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA
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Zhang C, Hoang G, Attarwala N, Cooper AJL, Asaka R, Le A. Metabolic Recycling Enhances Proliferation in MYC-Transformed Lymphoma B Cells. Adv Biol (Weinh) 2023; 7:e2200233. [PMID: 36417583 PMCID: PMC10375452 DOI: 10.1002/adbi.202200233] [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: 08/25/2022] [Revised: 10/10/2022] [Indexed: 11/27/2022]
Abstract
Relapses negatively impact cancer patient survival due to the tumorigenesis ability of surviving cancer cells post-therapy. Efforts are needed to better understand and combat this problem. This study hypothesized that dead cell debris post-radiation therapy creates an advantageous microenvironment rich in metabolic materials promoting the growth of remaining live cancer cells. In this study, live cancer cells are co-cultured with dead cancer cells eradicated by UV radiation to mimic a post-therapy environment. Isotopic labeling metabolomics is used to investigate the metabolic behavior of cancer cells grown in a post-radiation-therapy environment. It is found that post-UV-eradicated dead cancer cells serve as nutritional sources of "off-the-shelf" and precursor metabolites for surviving cancer cells. The surviving cancer cells then take up these metabolites, integrate and upregulate multiple vital metabolic processes, thereby significantly increasing growth in vitro and probably in vivo beyond their intrinsic fast-growing characteristics. Importantly, this active metabolite uptake behavior is only observed in oncogenic but not in non-oncogenic cells, presenting opportunities for therapeutic approaches to interrupt the active uptake process of oncogenic cells without affecting normal cells. The process by which living cancer cells re-use vital metabolites released by dead cancer cells post-therapy is coined in this study as "metabolic recycling" of oncogenic cells.
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Affiliation(s)
- Cissy Zhang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Giang Hoang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Nabeel Attarwala
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA
| | - Ryoichi Asaka
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Anne Le
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, MD, 21218, USA
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Zhang C, Hoang G, Attarwala N, Cooper AJL, Asaka R, Le A. Metabolic Recycling Enhances Proliferation in MYC‐Transformed Lymphoma B Cells (Adv. Biology 2/2023). Adv Biol (Weinh) 2023. [DOI: 10.1002/adbi.202370021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Cooper AJL, Dorai T, Pinto JT, Denton TT. α-Ketoglutaramate-A key metabolite contributing to glutamine addiction in cancer cells. Front Med (Lausanne) 2022; 13:1035335. [PMID: 36404951 PMCID: PMC9671947 DOI: 10.3389/fmed.2022.1035335] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/10/2022] [Indexed: 08/27/2023] Open
Affiliation(s)
- Arthur J. L. Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
| | - Thambi Dorai
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
- Department of Urology, New York Medical College, Valhalla, NY, United States
| | - John T. Pinto
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
| | - Travis T. Denton
- Department Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University Health Sciences Spokane, Spokane, WA, United States
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University Health Sciences Spokane, Spokane, WA, United States
- Steve Gleason Institute for Neuroscience, Washington State University Health Sciences Spokane, Spokane, WA, United States
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Müller N, Warwick T, Noack K, Malacarne PF, Cooper AJL, Weissmann N, Schröder K, Brandes RP, Rezende F. Reactive Oxygen Species Differentially Modulate the Metabolic and Transcriptomic Response of Endothelial Cells. Antioxidants (Basel) 2022; 11:antiox11020434. [PMID: 35204316 PMCID: PMC8869421 DOI: 10.3390/antiox11020434] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 02/04/2023] Open
Abstract
Reactive oxygen species (ROS) are important mediators of both physiological and pathophysiological signal transduction in the cardiovascular system. The effects of ROS on cellular processes depend on the concentration, localization, and duration of exposure. Cellular stress response mechanisms have evolved to mitigate the negative effects of acute oxidative stress. In this study, we investigate the short-term and long-term metabolic and transcriptomic response of human umbilical vein endothelial cells (HUVEC) to different types and concentrations of ROS. To generate intracellular H2O2, we utilized a lentiviral chemogenetic approach for overexpression of human D-amino acid oxidase (DAO). DAO converts D-amino acids into their corresponding imino acids and H2O2. HUVEC stably overexpressing DAO (DAO-HUVEC) were exposed to D-alanine (3 mM), exogenous H2O2 (10 µM or 300 µM), or menadione (5 µM) for various timepoints and subjected to global untargeted metabolomics (LC-MS/MS) and RNAseq by MACE (Massive analysis of cDNA ends). A total of 300 µM H2O2 led to pronounced changes on both the metabolic and transcriptomic level. In particular, metabolites linked to redox homeostasis, energy-generating pathways, and nucleotide metabolism were significantly altered. Furthermore, 300 µM H2O2 affected genes related to the p53 pathway and cell cycle. In comparison, the effects of menadione and DAO-derived H2O2 mainly occurred at gene expression level. Collectively, all types of ROS led to subtle changes in the expression of ribosomal genes. Our results show that different types and concentration of ROS lead to a different metabolic and transcriptomic response in endothelial cells.
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Affiliation(s)
- Niklas Müller
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern Kai 7, 60590 Frankfurt, Germany; (N.M.); (T.W.); (K.N.); (P.F.M.); (K.S.); (R.P.B.)
- German Center of Cardiovascular Research (DZHK), Partner Site Rhein Main, 60590 Frankfurt, Germany
| | - Timothy Warwick
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern Kai 7, 60590 Frankfurt, Germany; (N.M.); (T.W.); (K.N.); (P.F.M.); (K.S.); (R.P.B.)
- German Center of Cardiovascular Research (DZHK), Partner Site Rhein Main, 60590 Frankfurt, Germany
| | - Kurt Noack
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern Kai 7, 60590 Frankfurt, Germany; (N.M.); (T.W.); (K.N.); (P.F.M.); (K.S.); (R.P.B.)
- German Center of Cardiovascular Research (DZHK), Partner Site Rhein Main, 60590 Frankfurt, Germany
| | - Pedro Felipe Malacarne
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern Kai 7, 60590 Frankfurt, Germany; (N.M.); (T.W.); (K.N.); (P.F.M.); (K.S.); (R.P.B.)
- German Center of Cardiovascular Research (DZHK), Partner Site Rhein Main, 60590 Frankfurt, Germany
| | - Arthur J. L. Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA;
| | - Norbert Weissmann
- Justus Excellence Cluster Cardio-Pulmonary Institute (CPI), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35390 Giessen, Germany;
| | - Katrin Schröder
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern Kai 7, 60590 Frankfurt, Germany; (N.M.); (T.W.); (K.N.); (P.F.M.); (K.S.); (R.P.B.)
- German Center of Cardiovascular Research (DZHK), Partner Site Rhein Main, 60590 Frankfurt, Germany
| | - Ralf P. Brandes
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern Kai 7, 60590 Frankfurt, Germany; (N.M.); (T.W.); (K.N.); (P.F.M.); (K.S.); (R.P.B.)
- German Center of Cardiovascular Research (DZHK), Partner Site Rhein Main, 60590 Frankfurt, Germany
| | - Flávia Rezende
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern Kai 7, 60590 Frankfurt, Germany; (N.M.); (T.W.); (K.N.); (P.F.M.); (K.S.); (R.P.B.)
- German Center of Cardiovascular Research (DZHK), Partner Site Rhein Main, 60590 Frankfurt, Germany
- Correspondence: ; Tel.: +49-69-6301-85321; Fax: +49-69-6301-7668
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Epova EY, Shevelev AB, Shurubor YI, Cooper AJL, Biryukova YK, Bogdanova ES, Tyno YY, Lebedeva AA, Krasnikov BF. A novel efficient producer of human ω-amidase (Nit2) in Escherichia coli. Anal Biochem 2021; 632:114332. [PMID: 34391728 DOI: 10.1016/j.ab.2021.114332] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 07/09/2021] [Accepted: 08/06/2021] [Indexed: 11/25/2022]
Abstract
Nit2/ω-amidase catalyzes the hydrolysis of α-ketoglutaramate (KGM, the α-keto acid analogue of glutamine) to α-ketoglutarate and ammonia. The enzyme also catalyzes the amide hydrolysis of monoamides of 4- and 5-C-dicarboxylates, including α-ketosuccinamate (KSM, the α-keto acid analogue of asparagine) and succinamate (SM). Here we describe an inexpensive procedure for high-yield expression of human Nit2 (hNit2) in Escherichia coli and purification of the expressed protein. This work includes: 1) the design of a genetic construct (pQE-Nit22) obtained from the previously described construct (pQE-Nit2) by replacing rare codons within an 81 bp-long DNA fragment "preferred" by E. coli near the translation initiation site; 2) methods for producing and maintaining the pQE-Nit22 construct; 3) purification of recombinant hNit2; and 4) activity measurements of the purified enzyme with KGM and SM. Important features of the hNit2 gene within the pQE-Nit22 construct are: 1) optimized codon composition, 2) the presence of an N-terminus His6 tag immediately after the initiating codon ATG (Met) that permits efficient purification of the end-product on a Ni-NTA-agarose column. We anticipate that the availability of high yield hNit2/ω-amidase will be helpful in elucidating the normal and pathological roles of this enzyme and in the design of specific inhibitors.
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Affiliation(s)
- Ekaterina Yu Epova
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Alexei B Shevelev
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | | | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA
| | - Yulia K Biryukova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Elena S Bogdanova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia; Plekhanov Russian University of Economics, Moscow, Russia
| | - Yaroslav Ya Tyno
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Anna A Lebedeva
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Boris F Krasnikov
- Centre for Strategic Planning of FMBA of the Russian Federation, Moscow, Russia; Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA.
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Cooper AJL, Hanover J. A tribute to William (Bill) B. Jakoby. Anal Biochem 2021; 644:114315. [PMID: 34303692 DOI: 10.1016/j.ab.2021.114315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arthur J L Cooper
- Professor emeritus of Biochemistry and Molecular Biology, Department of Biochemistry and Molecular Biology, New York Medical College, USA.
| | - John Hanover
- Laboratory of Cell and Molecular Biology, NIDDK, National Institutes of Health, USA.
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Hoang G, Zhang C, Attarwala N, Jung JG, Cooper AJL, Le A. Uncovering Metabolic Reservoir Cycles in MYC-Transformed Lymphoma B cells Using Stable Isotope Resolved Metabolomics. Anal Biochem 2021; 632:114206. [PMID: 33894159 DOI: 10.1016/j.ab.2021.114206] [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] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/17/2021] [Accepted: 04/10/2021] [Indexed: 10/21/2022]
Abstract
The use of metabolomics technologies and stable isotope labeling recently enabled us to discover an unexpected role of N-acetyl-aspartyl-glutamate (NAAG): NAAG is a glutamate reservoir for cancer cells. In the current study, we first found that glucose carbon contributes to the formation of NAAG and its precursors via glycolysis, demonstrating the existence of a glucose-NAAG-glutamate cycle in cancer cells. Second, we found that glucose carbon and, unexpectedly, glutamine carbon contribute to the formation of lactate via glutaminolysis. Importantly, lactate carbon can be incorporated into glucose via gluconeogenesis, demonstrating the existence of a glutamine-lactate-glucose cycle. While a glucose-lactate-glucose cycle was expected, the finding of a glutamine-lactate-glucose cycle was unforeseen. And third, we discovered that glutamine carbon is incorporated into γ-aminobutyric acid (GABA), revealing a glutamate-GABA-succinate cycle. Thus, NAAG, lactate, and GABA can play important roles as storage molecules for glutamate, glucose, and succinate carbon in oncogenic MYC-transformed P493 lymphoma B cells (MYC-ON cells) but not in non-oncogenic MYC-OFF cells. Altogether, examining the isotopic labeling patterns of metabolites derived from labeled 13C6-glucose or 13C515N2-glutamine helped reveal the presence of what we have named "metabolic reservoir cycles" in oncogenic cells.
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Affiliation(s)
- Giang Hoang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
| | - Cissy Zhang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nabeel Attarwala
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Jin G Jung
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY; ORCID: https://orcid.org/0000-0002-9143-8504
| | - Anne Le
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD.
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Shurubor YI, Cooper AJL, Krasnikov AB, Isakova EP, Deryabina YI, Beal MF, Krasnikov BF. Changes of Coenzyme A and Acetyl-Coenzyme A Concentrations in Rats after a Single-Dose Intraperitoneal Injection of Hepatotoxic Thioacetamide Are Not Consistent with Rapid Recovery. Int J Mol Sci 2020; 21:E8918. [PMID: 33255464 PMCID: PMC7727790 DOI: 10.3390/ijms21238918] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/12/2022] Open
Abstract
Small biomolecules, such as coenzyme A (CoA) and acetyl coenzyme A (acetyl-CoA), play vital roles in the regulation of cellular energy metabolism. In this paper, we evaluated the delayed effect of the potent hepatotoxin thioacetamide (TAA) on the concentrations of CoA and acetyl-CoA in plasma and in different rat tissues. Administration of TAA negatively affects liver function and leads to the development of hepatic encephalopathy (HE). In our experiments, rats were administered a single intraperitoneal injection of TAA at doses of 200, 400, or 600 mg/kg. Plasma, liver, kidney, and brain samples were collected six days after the TAA administration, a period that has been suggested to allow for restoration of liver function. The concentrations of CoA and acetyl-CoA in the group of rats exposed to different doses of TAA were compared to those observed in healthy rats. The results obtained indicate that even a single administration of TAA to rats is sufficient to alter the physiological balance of CoA and acetyl-CoA in the plasma and tissues of rats for an extended period of time. The initial concentrations of CoA and acetyl-CoA were not restored even after the completion of the liver regeneration process.
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Affiliation(s)
- Yevgeniya I. Shurubor
- Center for Strategic Planning and Management of Medical and Biological Health Risks, Federal Medical-Biological Agency of The Russian Federation, 119121 Moscow, Russia;
| | - Arthur J. L. Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
| | | | - Elena P. Isakova
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (E.P.I.); (Y.I.D.)
| | - Yulia I. Deryabina
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (E.P.I.); (Y.I.D.)
| | - M. Flint Beal
- Department of Neurology, The Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10021, USA;
| | - Boris F. Krasnikov
- Center for Strategic Planning and Management of Medical and Biological Health Risks, Federal Medical-Biological Agency of The Russian Federation, 119121 Moscow, Russia;
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
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Dorai T, Dorai B, Pinto JT, Grasso M, Cooper AJL. High Levels of Glutaminase II Pathway Enzymes in Normal and Cancerous Prostate Suggest a Role in 'Glutamine Addiction'. Biomolecules 2019; 10:biom10010002. [PMID: 31861280 PMCID: PMC7022959 DOI: 10.3390/biom10010002] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [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: 12/09/2019] [Accepted: 12/13/2019] [Indexed: 12/17/2022] Open
Abstract
Abstract: Many tumors readily convert l-glutamine to α-ketoglutarate. This conversion is almost invariably described as involving deamidation of l-glutamine to l-glutamate followed by a transaminase (or dehydrogenase) reaction. However, mammalian tissues possess another pathway for conversion of l-glutamine to α-ketoglutarate, namely the glutaminase II pathway: l-Glutamine is transaminated to α-ketoglutaramate, which is then deamidated to α-ketoglutarate by ω-amidase. Here we show that glutamine transaminase and ω-amidase specific activities are high in normal rat prostate. Immunohistochemical analyses revealed that glutamine transaminase K (GTK) and ω-amidase are present in normal and cancerous human prostate and that expression of these enzymes increases in parallel with aggressiveness of the cancer cells. Our findings suggest that the glutaminase II pathway is important in providing anaplerotic carbon to the tricarboxylic acid (TCA) cycle, closing the methionine salvage pathway, and in the provision of citrate carbon in normal and cancerous prostate. Finally, our data also suggest that selective inhibitors of GTK and/or ω-amidase may be clinically important for treatment of prostate cancer. In conclusion, the demonstration of a prominent glutaminase II pathway in prostate cancer cells and increased expression of the pathway with increasing aggressiveness of tumor cells provides a new perspective on 'glutamine addiction' in cancers.
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Affiliation(s)
- Thambi Dorai
- Department of Urology, New York Medical College, Valhalla, NY 10595, USA; (T.D.); (M.G.)
- Department of Biochemistry & Molecular Biology, New York Medical College, Valhalla, NY 10595, USA;
| | - Bhuvaneswari Dorai
- Department of Pathology, Montefiore-Nyack Hospital, Nyack, NY 10960, USA;
| | - John T. Pinto
- Department of Biochemistry & Molecular Biology, New York Medical College, Valhalla, NY 10595, USA;
| | - Michael Grasso
- Department of Urology, New York Medical College, Valhalla, NY 10595, USA; (T.D.); (M.G.)
| | - Arthur J. L. Cooper
- Department of Biochemistry & Molecular Biology, New York Medical College, Valhalla, NY 10595, USA;
- Correspondence: ; Tel.: +1-914-594-3330; Fax: +1-914-594-4058
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13
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Udupa S, Nguyen S, Hoang G, Nguyen T, Quinones A, Pham K, Asaka R, Nguyen K, Zhang C, Elgogary A, Jung JG, Xu Q, Fu J, Thomas AG, Tsukamoto T, Hanes J, Slusher BS, Cooper AJL, Le A. Front Cover: Upregulation of the Glutaminase II Pathway Contributes to Glutamate Production upon Glutaminase 1 Inhibition in Pancreatic Cancer. Proteomics 2019. [DOI: 10.1002/pmic.201970191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Udupa S, Nguyen S, Hoang G, Nguyen T, Quinones A, Pham K, Asaka R, Nguyen K, Zhang C, Elgogary A, Jung JG, Xu Q, Fu J, Thomas AG, Tsukamoto T, Hanes J, Slusher BS, Cooper AJL, Le A. Upregulation of the Glutaminase II Pathway Contributes to Glutamate Production upon Glutaminase 1 Inhibition in Pancreatic Cancer. Proteomics 2019; 19:e1800451. [PMID: 31231915 PMCID: PMC6851409 DOI: 10.1002/pmic.201800451] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/07/2019] [Indexed: 12/18/2022]
Abstract
The targeting of glutamine metabolism specifically via pharmacological inhibition of glutaminase 1 (GLS1) has been translated into clinical trials as a novel therapy for several cancers. The results, though encouraging, show room for improvement in terms of tumor reduction. In this study, the glutaminase II pathway is found to be upregulated for glutamate production upon GLS1 inhibition in pancreatic tumors. Moreover, genetic suppression of glutamine transaminase K (GTK), a key enzyme of the glutaminase II pathway, leads to the complete inhibition of pancreatic tumorigenesis in vivo unveiling GTK as a new metabolic target for cancer therapy. These results suggest that current trials using GLS1 inhibition as a therapeutic approach targeting glutamine metabolism in cancer should take into account the upregulation of other metabolic pathways that can lead to glutamate production; one such pathway is the glutaminase II pathway via GTK.
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Affiliation(s)
- Sunag Udupa
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, MD, 21218, USA
| | - Stephanie Nguyen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Giang Hoang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Tu Nguyen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Addison Quinones
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Khoa Pham
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Ryoichi Asaka
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Kiet Nguyen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Cissy Zhang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Amira Elgogary
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Jin G Jung
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Qingguo Xu
- Department of Ophthalmology and Wilmer Eye Institute Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Jie Fu
- Department of Ophthalmology and Wilmer Eye Institute Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Ajit G Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Takashi Tsukamoto
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Justin Hanes
- Department of Ophthalmology and Wilmer Eye Institute Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, MD, 21218, USA
| | - Barbara S Slusher
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA
| | - Anne Le
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
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15
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Niehaus TD, Folz J, McCarty DR, Cooper AJL, Moraga Amador D, Fiehn O, Hanson AD. Identification of a metabolic disposal route for the oncometabolite S-(2-succino)cysteine in Bacillus subtilis. J Biol Chem 2018; 293:8255-8263. [PMID: 29626092 DOI: 10.1074/jbc.ra118.002925] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/04/2018] [Indexed: 01/21/2023] Open
Abstract
Cellular thiols such as cysteine spontaneously and readily react with the respiratory intermediate fumarate, resulting in the formation of stable S-(2-succino)-adducts. Fumarate-mediated succination of thiols increases in certain tumors and in response to glucotoxicity associated with diabetes. Therefore, S-(2-succino)-adducts such as S-(2-succino)cysteine (2SC) are considered oncometabolites and biomarkers for human disease. No disposal routes for S-(2-succino)-compounds have been reported prior to this study. Here, we show that Bacillus subtilis metabolizes 2SC to cysteine using a pathway encoded by the yxe operon. The first step is N-acetylation of 2SC followed by an oxygenation that we propose results in the release of oxaloacetate and N-acetylcysteine, which is deacetylated to give cysteine. Knockouts of the genes predicted to mediate each step in the pathway lose the ability to grow on 2SC as the sulfur source and accumulate the expected upstream metabolite(s). We further show that N-acetylation of 2SC relieves toxicity. This is the first demonstration of a metabolic disposal route for any S-(2-succino)-compound, paving the way toward the identification of corresponding pathways in other species.
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Affiliation(s)
- Thomas D Niehaus
- Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611.
| | - Jacob Folz
- West Coast Metabolomics Center, University of California, Davis, California 95616
| | - Donald R McCarty
- Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York 10595
| | - David Moraga Amador
- Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32611
| | - Oliver Fiehn
- West Coast Metabolomics Center, University of California, Davis, California 95616
| | - Andrew D Hanson
- Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611.
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16
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Jeitner TM, Kristoferson E, Azcona JA, Pinto JT, Stalnecker C, Erickson JW, Kung HF, Li J, Ploessl K, Cooper AJL. Fluorination at the 4 position alters the substrate behavior of L-glutamine and L-glutamate: Implications for positron emission tomography of neoplasias. J Fluor Chem 2017; 192:58-67. [PMID: 28546645 DOI: 10.1016/j.jfluchem.2016.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Two 4-fluoro-L-glutamine diastereoisomers [(2S,4R)-4-FGln, (2S,4S)-4-FGln] were previously developed for positron emission tomography. Label uptake into two tumor cell types was greater with [18F](2S,4R)-4-FGln than with [18F](2S,4S)-4-FGln. In the present work we investigated the enzymology of two diastereoisomers of 4-FGln, two diastereoisomers of 4-fluoroglutamate (4-FGlu) (potential metabolites of the 4-FGln diastereoisomers) and another fluoro-derivative of L-glutamine [(2S,4S)-4-(3-fluoropropyl)glutamine (FP-Gln)]. The two 4-FGlu diastereoisomers were found to be moderate-to-good substrates relative to L-glutamate of glutamate dehydrogenase, aspartate aminotransferase and alanine aminotransferase. Additionally, alanine aminotransferase was shown to catalyze an unusual γ-elimination reaction with both 4-FGlu diastereoisomers. Both 4-FGlu diastereoisomers were shown to be poor substrates, but strong inhibitors of glutamine synthetase. Both 4-FGln diastereoisomers were shown to be poor substrates compared to L-glutamine of glutamine transaminase L and α-aminoadipate aminotransferase. However, (2S,4R)-4-FGln was found to be a poor substrate of glutamine transaminase K, whereas (2S,4S)-4-FGln was shown to be an excellent substrate. By contrast, FP-Gln was found to be a poor substrate of all enzymes examined. Evidently, substitution of H in position 4 by F in L-glutamine/L-glutamate has moderate-to-profound effects on enzyme-catalyzed reactions. The present results: 1) show that 4-FGln and 4-FGlu diastereoisomers may be useful for studying active site topology of glutamate- and glutamine-utilizing enzymes; 2) provide a framework for understanding possible metabolic transformations in tumors of 18F-labeled (2S,4R)-4-FGln, (2S,4S)-4-FGln, (2S,4R)-4-FGlu or (2S,4S)-4-FGlu; and 3) show that [18F]FP-Gln is likely to be much less metabolically active in vivo than are the [18F]4-FGln diastereoisomers.
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Affiliation(s)
- Thomas M Jeitner
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
| | - Eva Kristoferson
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
| | - Juan A Azcona
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
| | - John T Pinto
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
| | - Clint Stalnecker
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jon W Erickson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Hank F Kung
- Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jianyong Li
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Karl Ploessl
- Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
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17
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Cudalbu C, Cooper AJL. Editorial for the special issue on introduction to in vivo Magnetic Resonance Spectroscopy (MRS): A method to non-invasively study metabolism. Anal Biochem 2017; 529:1-3. [PMID: 28522309 DOI: 10.1016/j.ab.2017.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL-CIBM, Lausanne, Switzerland.
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, USA
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18
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Hallen A, Cooper AJL. Erratum to: Ketimine Reductase: Reciprocal Control of Thyroid Hormone Binding and the Pipecolate Pathway in Brain. Neurochem Res 2017; 42:1580. [DOI: 10.1007/s11064-017-2210-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Hariharan VA, Denton TT, Paraszcszak S, McEvoy K, Jeitner TM, Krasnikov BF, Cooper AJL. The Enzymology of 2-Hydroxyglutarate, 2-Hydroxyglutaramate and 2-Hydroxysuccinamate and Their Relationship to Oncometabolites. Biology (Basel) 2017; 6:biology6020024. [PMID: 28358347 PMCID: PMC5485471 DOI: 10.3390/biology6020024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 12/17/2022]
Abstract
Many enzymes make "mistakes". Consequently, repair enzymes have evolved to correct these mistakes. For example, lactate dehydrogenase (LDH) and mitochondrial malate dehydrogenase (mMDH) slowly catalyze the reduction of 2-oxoglutarate (2-OG) to the oncometabolite l-2-hydroxyglutarate (l-2-HG). l-2-HG dehydrogenase corrects this error by converting l-2-HG to 2-OG. LDH also catalyzes the reduction of the oxo group of 2-oxoglutaramate (2-OGM; transamination product of l-glutamine). We show here that human glutamine synthetase (GS) catalyzes the amidation of the terminal carboxyl of both the l- and d- isomers of 2-HG. The reaction of 2-OGM with LDH and the reaction of l-2-HG with GS generate l-2-hydroxyglutaramate (l-2-HGM). We also show that l-2-HGM is a substrate of human ω-amidase. The product (l-2-HG) can then be converted to 2-OG by l-2-HG dehydrogenase. Previous work showed that 2-oxosuccinamate (2-OSM; transamination product of l-asparagine) is an excellent substrate of LDH. Finally, we also show that human ω-amidase converts the product of this reaction (i.e., l-2-hydroxysuccinamate; l-2-HSM) to l-malate. Thus, ω-amidase may act together with hydroxyglutarate dehydrogenases to repair certain "mistakes" of GS and LDH. The present findings suggest that non-productive pathways for nitrogen metabolism occur in mammalian tissues in vivo. Perturbations of these pathways may contribute to symptoms associated with hydroxyglutaric acidurias and to tumor progression. Finally, methods for the synthesis of l-2-HGM and l-2-HSM are described that should be useful in determining the roles of ω-amidase/4- and 5-C compounds in photorespiration in plants.
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Affiliation(s)
- Vivek A Hariharan
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Travis T Denton
- Department of Pharmaceutical Sciences, Washington State University, College of Pharmacy, Spokane, WA 99210-1495, USA.
| | - Sarah Paraszcszak
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Kyle McEvoy
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Thomas M Jeitner
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Boris F Krasnikov
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
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20
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Bémeur C, Cudalbu C, Dam G, Thrane AS, Cooper AJL, Rose CF. Brain edema: a valid endpoint for measuring hepatic encephalopathy? Metab Brain Dis 2016; 31:1249-1258. [PMID: 27272740 DOI: 10.1007/s11011-016-9843-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [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: 10/05/2015] [Accepted: 05/19/2016] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a major complication of liver failure/disease which frequently develops during the progression of end-stage liver disease. This metabolic neuropsychiatric syndrome involves a spectrum of symptoms, including cognition impairment, attention deficits and motor dysfunction which eventually can progress to coma and death. Pathologically, HE is characterized by swelling of the astrocytes which consequently leads to brain edema, a common feature found in patients with acute liver failure (ALF) as well as in cirrhotic patients suffering from HE. The pathogenic factors involved in the onset of astrocyte swelling and brain edema in HE are unresolved. However, the role of astrocyte swelling/brain edema in the development of HE remains ambiguous and therefore measuring brain edema as an endpoint to evaluate HE is questioned. The following review will determine the effect of astrocyte swelling and brain edema on neurological function, discuss the various possible techniques to measure brain edema and lastly to propose a number of neurobehavioral tests to evaluate HE.
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Affiliation(s)
- Chantal Bémeur
- Département de nutrition, Université de Montréal, Montréal, Québec, Canada
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Québec, Canada
| | - Cristina Cudalbu
- Centre d'Imagerie Biomédicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Gitte Dam
- Department of Medicine V (Hepatology and Gastroenterology), Aarhus, Denmark
| | - Alexander S Thrane
- Department of Ophthalmology, Haukeland University Hospital, 5012, Bergen, Norway
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York, 14642, USA
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York, 10595, USA
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Québec, Canada.
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21
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Cruz NF, Dienel GA, Patrick PA, Cooper AJL. Organ Distribution of 13N Following Intravenous Injection of [ 13N]Ammonia into Portacaval-Shunted Rats. Neurochem Res 2016; 42:1683-1696. [PMID: 27822667 DOI: 10.1007/s11064-016-2096-5] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/27/2016] [Accepted: 10/31/2016] [Indexed: 12/18/2022]
Abstract
Ammonia is neurotoxic, and chronic hyperammonemia is thought to be a major contributing factor to hepatic encephalopathy in patients with liver disease. Portacaval shunting of rats is used as an animal model to study the detrimental metabolic effects of elevated ammonia levels on body tissues, particularly brain and testes that are deleteriously targeted by high blood ammonia. In normal adult rats, the initial uptake of label (expressed as relative concentration) in these organs was relatively low following a bolus intravenous injection of [13N]ammonia compared with lungs, kidneys, liver, and some other organs. The objective of the present study was to determine the distribution of label following intravenous administration of [13N]ammonia among 14 organs in portacaval-shunted rats at 12 weeks after shunt construction. At an early time point (12 s) following administration of [13N]ammonia the relative concentration of label was highest in lung with lower, but still appreciable relative concentrations in kidney and heart. Clearance of 13N from blood and kidney tended to be slower in portacaval-shunted rats versus normal rats during the 2-10 min interval after the injection. At later times post injection, brain and testes tended to have higher-than-normal 13N levels, whereas many other tissues had similar levels in both groups. Thus, reduced removal of ammonia from circulating blood by the liver diverts more ammonia to extrahepatic tissues, including brain and testes, and alters the nitrogen homeostasis in these tissues. These results emphasize the importance of treatment paradigms designed to reduce blood ammonia levels in patients with liver disease.
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Affiliation(s)
- Nancy F Cruz
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, USA
| | | | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY, 10595, USA.
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22
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Dorai T, Pinto JT, Cooper AJL. Sweetening of glutamine metabolism in cancer cells by Rho GTPases through convergence of multiple oncogenic signaling pathways. Transl Cancer Res 2016. [DOI: 10.21037/tcr.2016.07.43] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Lin CHS, Chen J, Zhang Z, Johnson GVW, Cooper AJL, Feola J, Bank A, Shein J, Ruotsalainen HJ, Pihlajaniemi TA, Goligorsky MS. Endostatin and transglutaminase 2 are involved in fibrosis of the aging kidney. Kidney Int 2016; 89:1281-92. [PMID: 27165830 DOI: 10.1016/j.kint.2016.01.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 01/25/2016] [Accepted: 01/28/2016] [Indexed: 12/21/2022]
Abstract
Endostatin (EST), an antiangiogenic factor, is enriched in aging kidneys. EST is also an interactive partner of transglutaminase 2 (TG2), an enzyme that cross-links extracellular matrix proteins. Here we tested whether EST and TG2 play a role in the fibrosis of aging. In wild-type mice, aging kidneys exhibited a 2- to 4-fold increase in TG2 paralleled by increased cross-linked extracellular matrix proteins and fibrosis. Mice transgenic to express EST showed renal fibrosis at a young age. One-month delivery of EST via minipumps to young mice showed increased renal fibrosis that became more robust when superimposed on folic acid-induced nephropathy. Upregulated TG2 and impaired renal function were apparent with EST delivery combined with folic acid-induced nephropathy. Subcapsular injection of TG2 and/or EST into kidneys of young mice not only induced interstitial fibrosis, but also increased the proportion of senescent cells. Thus, kidney fibrosis in aging may represent a natural outcome of upregulated EST and TG2, but more likely it appears to be a result of cumulative stresses occurring on the background of synergistically acting geronic (aging) proteins, EST and TG2.
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Affiliation(s)
- Chi Hua Sarah Lin
- Department of Medicine, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Pharmacology, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Physiology, Renal Research Institute, New York Medical College, Valhalla, New York, USA
| | - Jun Chen
- Department of Medicine, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Pharmacology, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Physiology, Renal Research Institute, New York Medical College, Valhalla, New York, USA
| | - Zhongtao Zhang
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York, USA
| | - Gail V W Johnson
- Department of Anesthesiology, University of Rochester, Rochester, New York, USA
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York, USA
| | - Julianne Feola
- Department of Anesthesiology, University of Rochester, Rochester, New York, USA
| | - Alexander Bank
- Department of Medicine, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Pharmacology, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Physiology, Renal Research Institute, New York Medical College, Valhalla, New York, USA
| | - Jonathan Shein
- Department of Medicine, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Pharmacology, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Physiology, Renal Research Institute, New York Medical College, Valhalla, New York, USA
| | - Heli J Ruotsalainen
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Taina A Pihlajaniemi
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Michael S Goligorsky
- Department of Medicine, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Pharmacology, Renal Research Institute, New York Medical College, Valhalla, New York, USA; Department of Physiology, Renal Research Institute, New York Medical College, Valhalla, New York, USA.
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Hallen A, Cooper AJL, Smith JR, Jamie JF, Karuso P. Ketimine reductase/CRYM catalyzes reductive alkylamination of α-keto acids, confirming its function as an imine reductase. Amino Acids 2015; 47:2457-61. [PMID: 26173510 DOI: 10.1007/s00726-015-2044-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [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: 03/16/2015] [Accepted: 07/03/2015] [Indexed: 10/23/2022]
Abstract
Recently, crystalized mouse ketimine reductase/CRYM complexed with NADPH was found to have pyruvate bound in its active site. We demonstrate that the enzyme binds α-keto acids, such as pyruvate, in solution, and catalyzes the formation of N-alkyl-amino acids from alkylamines and α-keto acids (via reduction of imine intermediates), but at concentrations of these compounds not expected to be encountered in vivo. These findings confirm that, mechanistically, ketimine reductase/CRYM acts as a classical imine reductase and may explain the finding of bound pyruvate in the crystallized protein.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia.
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York, 10595, USA
| | - Jason R Smith
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia
| | - Joanne F Jamie
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia
| | - Peter Karuso
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia
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25
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Cooper AJL, Shurubor YI, Dorai T, Pinto JT, Isakova EP, Deryabina YI, Denton TT, Krasnikov BF. Erratum to: ω-Amidase: an underappreciated, but important enzyme in L-glutamine and L-asparagine metabolism; relevance to sulfur and nitrogen metabolism, tumor biology and hyperammonemic diseases. Amino Acids 2015; 47:2671-2. [PMID: 26503605 DOI: 10.1007/s00726-015-2115-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA.
| | - Yevgeniya I Shurubor
- Department of Neurology, The Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, 10021, USA.,A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 33 Leninsky Prospekt, Moscow, 119071, Russia
| | - Thambi Dorai
- Department of Urology, New York Medical College, Valhalla, NY, 10595, USA
| | - John T Pinto
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA
| | - Elena P Isakova
- A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 33 Leninsky Prospekt, Moscow, 119071, Russia
| | - Yulia I Deryabina
- A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 33 Leninsky Prospekt, Moscow, 119071, Russia
| | - Travis T Denton
- Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Spokane, WA, 99210, USA
| | - Boris F Krasnikov
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA.,A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 33 Leninsky Prospekt, Moscow, 119071, Russia
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26
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Affiliation(s)
- Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, United States
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27
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Jeitner TM, Battaile K, Cooper AJL. Critical Evaluation of the Changes in Glutamine Synthetase Activity in Models of Cerebral Stroke. Neurochem Res 2015; 40:2544-56. [DOI: 10.1007/s11064-015-1667-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/14/2015] [Accepted: 05/20/2015] [Indexed: 01/04/2023]
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Niehaus TD, Gerdes S, Hodge-Hanson K, Zhukov A, Cooper AJL, ElBadawi-Sidhu M, Fiehn O, Downs DM, Hanson AD. Genomic and experimental evidence for multiple metabolic functions in the RidA/YjgF/YER057c/UK114 (Rid) protein family. BMC Genomics 2015; 16:382. [PMID: 25975565 PMCID: PMC4433059 DOI: 10.1186/s12864-015-1584-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/27/2015] [Indexed: 12/03/2022] Open
Abstract
Background It is now recognized that enzymatic or chemical side-reactions can convert normal metabolites to useless or toxic ones and that a suite of enzymes exists to mitigate such metabolite damage. Examples are the reactive imine/enamine intermediates produced by threonine dehydratase, which damage the pyridoxal 5'-phosphate cofactor of various enzymes causing inactivation. This damage is pre-empted by RidA proteins, which hydrolyze the imines before they do harm. RidA proteins belong to the YjgF/YER057c/UK114 family (here renamed the Rid family). Most other members of this diverse and ubiquitous family lack defined functions. Results Phylogenetic analysis divided the Rid family into a widely distributed, apparently archetypal RidA subfamily and seven other subfamilies (Rid1 to Rid7) that are largely confined to bacteria and often co-occur in the same organism with RidA and each other. The Rid1 to Rid3 subfamilies, but not the Rid4 to Rid7 subfamilies, have a conserved arginine residue that, in RidA proteins, is essential for imine-hydrolyzing activity. Analysis of the chromosomal context of bacterial RidA genes revealed clustering with genes for threonine dehydratase and other pyridoxal 5'-phosphate-dependent enzymes, which fits with the known RidA imine hydrolase activity. Clustering was also evident between Rid family genes and genes specifying FAD-dependent amine oxidases or enzymes of carbamoyl phosphate metabolism. Biochemical assays showed that Salmonella enterica RidA and Rid2, but not Rid7, can hydrolyze imines generated by amino acid oxidase. Genetic tests indicated that carbamoyl phosphate overproduction is toxic to S. enterica cells lacking RidA, and metabolomic profiling of Rid knockout strains showed ten-fold accumulation of the carbamoyl phosphate-related metabolite dihydroorotate. Conclusions Like the archetypal RidA subfamily, the Rid2, and probably the Rid1 and Rid3 subfamilies, have imine-hydrolyzing activity and can pre-empt damage from imines formed by amine oxidases as well as by pyridoxal 5'-phosphate enzymes. The RidA subfamily has an additional damage pre-emption role in carbamoyl phosphate metabolism that has yet to be biochemically defined. Finally, the Rid4 to Rid7 subfamilies appear not to hydrolyze imines and thus remain mysterious. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1584-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thomas D Niehaus
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA.
| | - Svetlana Gerdes
- Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.
| | | | - Aleksey Zhukov
- Microbiology and Cell Science Department, University of Florida, Gainesville, FL, 32611, USA.
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA.
| | - Mona ElBadawi-Sidhu
- Metabolomics Core, UC Davis Genome Center, University of California Davis, Davis, CA, 95616, USA.
| | - Oliver Fiehn
- Metabolomics Core, UC Davis Genome Center, University of California Davis, Davis, CA, 95616, USA.
| | - Diana M Downs
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA.
| | - Andrew D Hanson
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA.
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29
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Abstract
Glutathionylation is generally a reversible posttranslational modification that occurs to cysteine residues that have been exposed to reactive oxygen species (P-SSG). This cyclical process can regulate various clusters of proteins, including those involved in critical cellular signaling functions. However, certain conditions can favor the formation of dehydroamino acids, such as 2,3-didehydroalanine (2,3-dehydroalanine, DHA) and 2,3-didehydrobutyrine (2,3-dehydrobutyrine), which can act as Michael acceptors. In turn, these can form Michael adducts with glutathione (GSH), resulting in the formation of a stable thioether conjugate, an irreversible process referred to as nonreducible glutathionylation. This is predicted to be prevalent in nature, particularly in more slowly turning over proteins. Such nonreducible glutathionylation can be distinguished from the more facile cycling signaling processes and is predicted to be of gerontological, toxicological, pharmacological, and oncological relevance. Here, we compare reversible and irreversible glutathionylation.
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Affiliation(s)
- Danyelle M Townsend
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Volodymyr I Lushchak
- Department of Biochemistry and Biotechnology, Vassyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York, USA.
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30
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Hallen A, Cooper AJL. Letter to the editor: μ-crystallin/CRYM functions as a ketimine-reducing enzyme and plays a role in thyroid hormone bioavailability due to strong inhibition/regulation by thyroid hormones. J Clin Endocrinol Metab 2015; 100:L15-6. [PMID: 25559540 DOI: 10.1210/jc.2014-3963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences Macquarie University N Ryde NSW 2109 Australia
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31
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Jeitner TM, Cooper AJL. Inhibition of human glutamine synthetase by L-methionine-S,R-sulfoximine-relevance to the treatment of neurological diseases. Metab Brain Dis 2014; 29:983-9. [PMID: 24136581 PMCID: PMC4180818 DOI: 10.1007/s11011-013-9439-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 09/18/2013] [Indexed: 01/22/2023]
Abstract
At high concentrations, the glutamine synthetase inhibitor L-methionine-S,R-sulfoximine (MSO) is a convulsant, especially in dogs. Nevertheless, sub-convulsive doses of MSO are neuroprotective in rodent models of hyperammonemia, acute liver disease, and amyotrophic lateral sclerosis and suggest MSO may be clinically useful. Previous work has also shown that much lower doses of MSO are required to produce convulsions in dogs than in primates. Evidence from the mid-20th century suggests that humans are also less sensitive. In the present work, the inhibition of recombinant human glutamine synthetase by MSO is shown to be biphasic-an initial reversible competitive inhibition (K i 1.19 mM) is followed by rapid irreversible inactivation. This K i value for the human enzyme accounts, in part, for relative insensitivity of primates to MSO and suggests that this inhibitor could be used to safely inhibit glutamine synthetase activity in humans.
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Affiliation(s)
- Thomas M Jeitner
- Neurosciences, Biomedical Research Core, Winthrop University Hospital, 222 Station Plaza North, Mineola, NY, 11501, USA,
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32
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Cooper AJL, Kuhara T. α-Ketoglutaramate: an overlooked metabolite of glutamine and a biomarker for hepatic encephalopathy and inborn errors of the urea cycle. Metab Brain Dis 2014; 29:991-1006. [PMID: 24234505 PMCID: PMC4020999 DOI: 10.1007/s11011-013-9444-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/21/2013] [Indexed: 01/16/2023]
Abstract
Glutamine metabolism is generally regarded as proceeding via glutaminase-catalyzed hydrolysis to glutamate and ammonia, followed by conversion of glutamate to α-ketoglutarate catalyzed by glutamate dehydrogenase or by a glutamate-linked aminotransferase (transaminase). However, another pathway exists for the conversion of glutamine to α-ketoglutarate that is often overlooked, but is widely distributed in nature. This pathway, referred to as the glutaminase II pathway, consists of a glutamine transaminase coupled to ω-amidase. Transamination of glutamine results in formation of the corresponding α-keto acid, namely, α-ketoglutaramate (KGM). KGM is hydrolyzed by ω-amidase to α-ketoglutarate and ammonia. The net glutaminase II reaction is: L - Glutamine + α - keto acid + H2O → α - ketoglutarate + L - amino acid + ammonia. In this mini-review the biochemical importance of the glutaminase II pathway is summarized, with emphasis on the key component KGM. Forty years ago it was noted that the concentration of KGM is increased in the cerebrospinal fluid (CSF) of patients with hepatic encephalopathy (HE) and that the level of KGM in the CSF correlates well with the degree of encephalopathy. In more recent work, we have shown that KGM is markedly elevated in the urine of patients with inborn errors of the urea cycle. It is suggested that KGM may be a useful biomarker for many hyperammonemic diseases including hepatic encephalopathy, inborn errors of the urea cycle, citrin deficiency and lysinuric protein intolerance.
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Affiliation(s)
- Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY, 10595, USA,
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33
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Pinto JT, Krasnikov BF, Alcutt S, Jones ME, Dorai T, Villar MT, Artigues A, Li J, Cooper AJL. Kynurenine aminotransferase III and glutamine transaminase L are identical enzymes that have cysteine S-conjugate β-lyase activity and can transaminate L-selenomethionine. J Biol Chem 2014; 289:30950-61. [PMID: 25231977 DOI: 10.1074/jbc.m114.591461] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three of the four kynurenine aminotransferases (KAT I, II, and IV) that synthesize kynurenic acid, a neuromodulator, are identical to glutamine transaminase K (GTK), α-aminoadipate aminotransferase, and mitochondrial aspartate aminotransferase, respectively. GTK/KAT I and aspartate aminotransferase/KAT IV possess cysteine S-conjugate β-lyase activity. The gene for the former enzyme, GTK/KAT I, is listed in mammalian genome data banks as CCBL1 (cysteine conjugate beta-lyase 1). Also listed, despite the fact that no β-lyase activity has been assigned to the encoded protein in the genome data bank, is a CCBL2 (synonym KAT III). We show that human KAT III/CCBL2 possesses cysteine S-conjugate β-lyase activity, as does mouse KAT II. Thus, depending on the nature of the substrate, all four KATs possess cysteine S-conjugate β-lyase activity. These present studies show that KAT III and glutamine transaminase L are identical enzymes. This report also shows that KAT I, II, and III differ in their ability to transaminate methyl-L-selenocysteine (MSC) and L-selenomethionine (SM) to β-methylselenopyruvate (MSP) and α-ketomethylselenobutyrate, respectively. Previous studies have identified these seleno-α-keto acids as potent histone deacetylase inhibitors. Methylselenol (CH3SeH), also purported to have chemopreventive properties, is the γ-elimination product of SM and the β-elimination product of MSC catalyzed by cystathionine γ-lyase (γ-cystathionase). KAT I, II, and III, in part, can catalyze β-elimination reactions with MSC generating CH3SeH. Thus, the anticancer efficacy of MSC and SM will depend, in part, on the endogenous expression of various KAT enzymes and cystathionine γ-lyase present in target tissue coupled with the ability of cells to synthesize in situ either CH3SeH and/or seleno-keto acid metabolites.
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Affiliation(s)
- John T Pinto
- From the Departments of Biochemistry and Molecular Biology and
| | | | - Steven Alcutt
- From the Departments of Biochemistry and Molecular Biology and
| | - Melanie E Jones
- From the Departments of Biochemistry and Molecular Biology and
| | - Thambi Dorai
- Urology, New York Medical College, Valhalla, New York 10595
| | - Maria T Villar
- the Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, and
| | - Antonio Artigues
- the Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, and
| | - Jianyong Li
- the Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
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34
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Toohey JI, Cooper AJL. Thiosulfoxide (sulfane) sulfur: new chemistry and new regulatory roles in biology. Molecules 2014; 19:12789-813. [PMID: 25153879 PMCID: PMC4170951 DOI: 10.3390/molecules190812789] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/11/2014] [Accepted: 08/12/2014] [Indexed: 11/24/2022] Open
Abstract
The understanding of sulfur bonding is undergoing change. Old theories on hypervalency of sulfur and the nature of the chalcogen-chalcogen bond are now questioned. At the same time, there is a rapidly expanding literature on the effects of sulfur in regulating biological systems. The two fields are inter-related because the new understanding of the thiosulfoxide bond helps to explain the newfound roles of sulfur in biology. This review examines the nature of thiosulfoxide (sulfane, S0) sulfur, the history of its regulatory role, its generation in biological systems, and its functions in cells. The functions include synthesis of cofactors (molybdenum cofactor, iron-sulfur clusters), sulfuration of tRNA, modulation of enzyme activities, and regulating the redox environment by several mechanisms (including the enhancement of the reductive capacity of glutathione). A brief review of the analogous form of selenium suggests that the toxicity of selenium may be due to over-reduction caused by the powerful reductive activity of glutathione perselenide.
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Affiliation(s)
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA.
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35
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Niehaus TD, Nguyen TND, Gidda SK, ElBadawi-Sidhu M, Lambrecht JA, McCarty DR, Downs DM, Cooper AJL, Fiehn O, Mullen RT, Hanson AD. Arabidopsis and maize RidA proteins preempt reactive enamine/imine damage to branched-chain amino acid biosynthesis in plastids. Plant Cell 2014; 26:3010-22. [PMID: 25070638 PMCID: PMC4145128 DOI: 10.1105/tpc.114.126854] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/02/2014] [Accepted: 07/08/2014] [Indexed: 05/19/2023]
Abstract
RidA (for Reactive Intermediate Deaminase A) proteins are ubiquitous, yet their function in eukaryotes is unclear. It is known that deleting Salmonella enterica ridA causes Ser sensitivity and that S. enterica RidA and its homologs from other organisms hydrolyze the enamine/imine intermediates that Thr dehydratase forms from Ser or Thr. In S. enterica, the Ser-derived enamine/imine inactivates a branched-chain aminotransferase; RidA prevents this damage. Arabidopsis thaliana and maize (Zea mays) have a RidA homolog that is predicted to be plastidial. Expression of either homolog complemented the Ser sensitivity of the S. enterica ridA mutant. The purified proteins hydrolyzed the enamines/imines formed by Thr dehydratase from Ser or Thr and protected the Arabidopsis plastidial branched-chain aminotransferase BCAT3 from inactivation by the Ser-derived enamine/imine. In vitro chloroplast import assays and in vivo localization of green fluorescent protein fusions showed that Arabidopsis RidA and Thr dehydratase are chloroplast targeted. Disrupting Arabidopsis RidA reduced root growth and raised the root and shoot levels of the branched-chain amino acid biosynthesis intermediate 2-oxobutanoate; Ser treatment exacerbated these effects in roots. Supplying Ile reversed the root growth defect. These results indicate that plastidial RidA proteins can preempt damage to BCAT3 and Ile biosynthesis by hydrolyzing the Ser-derived enamine/imine product of Thr dehydratase.
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Affiliation(s)
- Thomas D Niehaus
- Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Thuy N D Nguyen
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Satinder K Gidda
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Mona ElBadawi-Sidhu
- Metabolics Core, UC Davis Genome Center, University of California, Davis, California 95616
| | | | - Donald R McCarty
- Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
| | - Diana M Downs
- Department of Microbiology, University of Georgia, Athens, Georgia 30602
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York 10595
| | - Oliver Fiehn
- Metabolics Core, UC Davis Genome Center, University of California, Davis, California 95616
| | - Robert T Mullen
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Andrew D Hanson
- Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611
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36
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Abstract
Flavin-dependent monooxygenases and oxidoreductases are located at critical branch points in the biosynthesis and metabolism of cholesterol and vitamin D. These flavoproteins function as obligatory intermediates that accept 2 electrons from NAD(P)H with subsequent 1-electron transfers to a variety of cytochrome P450 (CYP) heme proteins within the mitochondria matrix (type I) and the (microsomal) endoplasmic reticulum (type II). The mode of electron transfer in these systems differs slightly in the number and form of the flavin prosthetic moiety. In the type I mitochondrial system, FAD-adrenodoxin reductase interfaces with adrenodoxin before electron transfer to CYP heme proteins. In the microsomal type II system, a diflavin (FAD/FMN)-dependent cytochrome P450 oxidoreductase [NAD(P)H-cytochrome P450 reductase (CPR)] donates electrons to a multitude of heme oxygenases. Both flavoenzyme complexes exhibit a commonality of function with all CYP enzymes and are crucial for maintaining a balance of cholesterol and vitamin D metabolites. Deficits in riboflavin availability, imbalances in the intracellular ratio of FAD to FMN, and mutations that affect flavin binding domains and/or interactions with client proteins result in marked structural alterations within the skeletal and central nervous systems similar to those of disorders (inborn errors) in the biosynthetic pathways that lead to cholesterol, steroid hormones, and vitamin D and their metabolites. Studies of riboflavin deficiency during embryonic development demonstrate congenital malformations similar to those associated with genetic alterations of the flavoenzymes in these pathways. Overall, a deeper understanding of the role of riboflavin in these pathways may prove essential to targeted therapeutic designs aimed at cholesterol and vitamin D metabolism.
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37
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Abstract
The lysine catabolism pathway differs in adult mammalian brain from that in extracerebral tissues. The saccharopine pathway is the predominant lysine degradative pathway in extracerebral tissues, whereas the pipecolate pathway predominates in adult brain. The two pathways converge at the level of ∆(1)-piperideine-6-carboxylate (P6C), which is in equilibrium with its open-chain aldehyde form, namely, α-aminoadipate δ-semialdehyde (AAS). A unique feature of the pipecolate pathway is the formation of the cyclic ketimine intermediate ∆(1)-piperideine-2-carboxylate (P2C) and its reduced metabolite L-pipecolate. A cerebral ketimine reductase (KR) has recently been identified that catalyzes the reduction of P2C to L-pipecolate. The discovery that this KR, which is capable of reducing not only P2C but also other cyclic imines, is identical to a previously well-described thyroid hormone-binding protein [μ-crystallin (CRYM)], may hold the key to understanding the biological relevance of the pipecolate pathway and its importance in the brain. The finding that the KR activity of CRYM is strongly inhibited by the thyroid hormone 3,5,3'-triiodothyronine (T3) has far-reaching biomedical and clinical implications. The inter-relationship between tryptophan and lysine catabolic pathways is discussed in the context of shared degradative enzymes and also potential regulation by thyroid hormones. This review traces the discoveries of enzymes involved in lysine metabolism in mammalian brain. However, there still remain unanswered questions as regards the importance of the pipecolate pathway in normal or diseased brain, including the nature of the first step in the pathway and the relationship of the pipecolate pathway to the tryptophan degradation pathway.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia,
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38
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Abstract
In a contribution to this Research Topic Erkki Somersalo and Daniela Calvetti carried out a mathematical analysis of neurotransmitter pathways in brain, modeling compartmental nitrogen flux among several major participants - ammonia, glutamine, glutamate, GABA, and selected amino acids. This analysis is important because cerebral nitrogen metabolism is perturbed in many diseases, including liver disease and inborn errors of the urea cycle. These diseases result in an elevation of blood ammonia, which is neurotoxic. Here, a brief description is provided of the discovery of cerebral metabolic compartmentation of nitrogen metabolism - a key feature of cerebral glutamate-glutamine and GABA-glutamine cycles. The work of Somersalo and Calvetti is discussed as a model for future studies of normal and pathological cerebral ammonia metabolism.
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Affiliation(s)
- Arthur J. L. Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, USA
- *Correspondence: Arthur J. L. Cooper, Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10520, USA e-mail:
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Hallen A, Jamie JF, Cooper AJL. Lysine metabolism in mammalian brain: an update on the importance of recent discoveries. Amino Acids 2013; 45:1249-72. [PMID: 24043460 DOI: 10.1007/s00726-013-1590-1] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 12/23/2022]
Abstract
The lysine catabolism pathway differs in adult mammalian brain from that in extracerebral tissues. The saccharopine pathway is the predominant lysine degradative pathway in extracerebral tissues, whereas the pipecolate pathway predominates in adult brain. The two pathways converge at the level of ∆(1)-piperideine-6-carboxylate (P6C), which is in equilibrium with its open-chain aldehyde form, namely, α-aminoadipate δ-semialdehyde (AAS). A unique feature of the pipecolate pathway is the formation of the cyclic ketimine intermediate ∆(1)-piperideine-2-carboxylate (P2C) and its reduced metabolite L-pipecolate. A cerebral ketimine reductase (KR) has recently been identified that catalyzes the reduction of P2C to L-pipecolate. The discovery that this KR, which is capable of reducing not only P2C but also other cyclic imines, is identical to a previously well-described thyroid hormone-binding protein [μ-crystallin (CRYM)], may hold the key to understanding the biological relevance of the pipecolate pathway and its importance in the brain. The finding that the KR activity of CRYM is strongly inhibited by the thyroid hormone 3,5,3'-triiodothyronine (T3) has far-reaching biomedical and clinical implications. The inter-relationship between tryptophan and lysine catabolic pathways is discussed in the context of shared degradative enzymes and also potential regulation by thyroid hormones. This review traces the discoveries of enzymes involved in lysine metabolism in mammalian brain. However, there still remain unanswered questions as regards the importance of the pipecolate pathway in normal or diseased brain, including the nature of the first step in the pathway and the relationship of the pipecolate pathway to the tryptophan degradation pathway.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia,
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Liu H, Gao Y, Zhang M, Qiu X, Cooper AJL, Niu L, Teng M. Structures of enzyme-intermediate complexes of yeast Nit2: insights into its catalytic mechanism and different substrate specificity compared with mammalian Nit2. Acta Crystallogr D Biol Crystallogr 2013; 69:1470-81. [PMID: 23897470 DOI: 10.1107/s0907444913009347] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 04/06/2013] [Indexed: 11/11/2022]
Abstract
The Nit (nitrilase-like) protein subfamily constitutes branch 10 of the nitrilase superfamily. Nit proteins are widely distributed in nature. Mammals possess two members of the Nit subfamily, namely Nit1 and Nit2. Based on sequence similarity, yeast Nit2 (yNit2) is a homologue of mouse Nit1, a tumour-suppressor protein whose substrate specificity is not yet known. Previous studies have shown that mammalian Nit2 (also a putative tumour suppressor) is identical to ω-amidase, an enzyme that catalyzes the hydrolysis of α-ketoglutaramate (α-KGM) and α-ketosuccinamate (α-KSM) to α-ketoglutarate (α-KG) and oxaloacetate (OA), respectively. In the present study, crystal structures of wild-type (WT) yNit2 and of WT yNit2 in complex with α-KG and with OA were determined. In addition, the crystal structure of the C169S mutant of yNit2 (yNit2-C169S) in complex with an endogenous molecule of unknown structure was also solved. Analysis of the structures revealed that α-KG and OA are covalently bound to Cys169 by the formation of a thioester bond between the sulfhydryl group of the cysteine residue and the γ-carboxyl group of α-KG or the β-carboxyl group of OA, reflecting the presumed reaction intermediates. However, an enzymatic assay suggests that α-KGM is a relatively poor substrate of yNit2. Finally, a ligand was found in the active site of yNit2-C169S that may be a natural substrate of yNit2 or an endogenous regulator of enzyme activity. These crystallographic analyses provide information on the mode of substrate/ligand binding at the active site of yNit2 and insights into the catalytic mechanism. These findings suggest that yNit2 may have broad biological roles in yeast, especially in regard to nitrogen homeostasis, and provide a framework for the elucidation of the substrate specificity and biological role of mammalian Nit1.
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Affiliation(s)
- Hejun Liu
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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Tsikas D, Denton TT, Cooper AJL. Comment on absorption of aminoethyl cysteine ketimine decarboxylated dimer in mice: effect on plasma antioxidant potential. J Agric Food Chem 2013; 61:6122-6124. [PMID: 23741990 DOI: 10.1021/jf401482c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Dimitrios Tsikas
- Institute of Clinical Pharmacology, Hannover Medical School , 30625 Hannover, Germany
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Abstract
Glutamine synthetase (GS) is highly active in astrocytes, and these cells are physiologically and morphologically compromised by hyperammonemia. Hyperammonemia in end-stage acute liver failure (ALF) is often associated with cerebral edema and astrocyte pathology/swelling. Many studies of animal models of hyperammonemia, and, more recently, nuclear magnetic resonance studies of liver disease patients, have shown that cerebral glutamine is elevated in hyperammonemia, contributing to the edema and encephalopathy. The GS inhibitor L-methionine-S,R-sulfoximine (MSO) is protective in animal models against acute ammonia intoxication. MSO is also an inhibitor of glutamate cysteine ligase, is converted to metabolic products, and causes convulsions at high doses. However, the susceptibility to MSO-induced convulsions is species dependent, with primates being relatively resistant. Moreover, it is possible to chronically maintain cerebral GS activity in mice at low levels by MSO treatment without any obvious untoward effects. Furthermore, MSO is protective in a mouse model of ALF. Extreme caution would be needed in administering MSO to patients. Nevertheless, inhibition of brain GS by MSO (or other GS inhibitors) may have therapeutic benefit in ALF.
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Affiliation(s)
- Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA.
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Hallen A, Jamie JF, Cooper AJL. Imine reductases: a comparison of glutamate dehydrogenase to ketimine reductases in the brain. Neurochem Res 2013; 39:527-41. [PMID: 23314864 DOI: 10.1007/s11064-012-0964-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/12/2012] [Accepted: 12/22/2012] [Indexed: 02/06/2023]
Abstract
A key intermediate in the glutamate dehydrogenase (GDH)-catalyzed reaction is an imine. Mechanistically, therefore, GDH exhibits similarities to the ketimine reductases. In the current review, we briefly discuss (a) the metabolic importance of the GDH reaction in liver and brain, (b) the mechanistic similarities between GDH and the ketimine reductases, (c) the metabolic importance of the brain ketimine reductases, and (d) the neurochemical consequences of defective ketimine reductases. Our review contains many historical references to the early work on amino acid metabolism. This work tends to be overlooked nowadays, but is crucial for a contemporary understanding of the central importance of ketimines in nitrogen and intermediary metabolism. The ketimine reductases are important enzymes linking nitrogen flow among several key amino acids, yet have been little studied. The cerebral importance of the ketimine reductases is an area of biomedical research that deserves far more attention.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia,
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Tsikas D, Evans CE, Denton TT, Mitschke A, Gutzki FM, Pinto JT, Khomenko T, Szabo S, Cooper AJL. Stable isotope gas chromatography-tandem mass spectrometry determination of aminoethylcysteine ketimine decarboxylated dimer in biological samples. Anal Biochem 2012; 430:4-15. [PMID: 22858756 DOI: 10.1016/j.ab.2012.07.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 07/20/2012] [Accepted: 07/23/2012] [Indexed: 01/04/2023]
Abstract
Aminoethylcysteine ketimine decarboxylated dimer (AECK-DD; systematic name: 1,2-3,4-5,6-7,8-octahydro-1,8a-diaza-4,6-dithiafluoren-9(8aH)-one) is a previously described metabolite of cysteamine that has been reported to be present in mammalian brain, urine, plasma, and cells in culture and vegetables and to possess potent antioxidative properties. Here, we describe a stable isotope gas chromatography-tandem mass spectrometry (GC-MS/MS) method for specific and sensitive determination of AECK-DD in biological samples. (13)C(2)-labeled AECK-DD was synthesized and used as the internal standard. Derivatization was carried out by N-pentafluorobenzylation with pentafluorobenzyl bromide in acetonitrile. Quantification was performed by selected reaction monitoring of the mass transitions m/z 328 to 268 for AECK-DD and m/z 330 to 270 for [(13)C(2)]AECK-DD in the electron capture negative ion chemical ionization mode. The procedure was systematically validated for human plasma and urine samples. AECK-DD was not detectable in human plasma above approximately 4nM but was present in urine samples of healthy humans at a maximal concentration of 46nM. AECK-DD was detectable in rat brain at very low levels of approximately 8pmol/g wet weight. Higher levels of AECK-DD were detected in mouse brain (∼1nmol/g wet weight). Among nine dietary vegetables evaluated, only shallots were found to contain trace amounts of AECK-DD (∼6.8pmol/g fresh tissue).
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Affiliation(s)
- Dimitrios Tsikas
- Institute of Clinical Pharmacology, Hannover Medical School, Hannover, Germany.
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Chien CH, Gao QZ, Cooper AJL, Lyu JH, Sheu SY. Structural insights into the catalytic active site and activity of human Nit2/ω-amidase: kinetic assay and molecular dynamics simulation. J Biol Chem 2012; 287:25715-26. [PMID: 22674578 DOI: 10.1074/jbc.m111.259119] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human nitrilase-like protein 2 (hNit2) is a putative tumor suppressor, recently identified as ω-amidase. hNit2/ω-amidase plays a crucial metabolic role by catalyzing the hydrolysis of α-ketoglutaramate (the α-keto analog of glutamine) and α-ketosuccinamate (the α-keto analog of asparagine), yielding α-ketoglutarate and oxaloacetate, respectively. Transamination between glutamine and α-keto-γ-methiolbutyrate closes the methionine salvage pathway. Thus, hNit2/ω-amidase links sulfur metabolism to the tricarboxylic acid cycle. To elucidate the catalytic specificity of hNit2/ω-amidase, we performed molecular dynamics simulations on the wild type enzyme and its mutants to investigate enzyme-substrate interactions. Binding free energies were computed to characterize factors contributing to the substrate specificity. The predictions resulting from these computations were verified by kinetic analyses and mutational studies. The activity of hNit2/ω-amidase was determined with α-ketoglutaramate and succinamate as substrates. We constructed three catalytic triad mutants (E43A, K112A, and C153A) and a mutant with a loop 116-128 deletion to validate the role of key residues and the 116-128 loop region in substrate binding and turnover. The molecular dynamics simulations successfully verified the experimental trends in the binding specificity of hNit2/ω-amidase toward various substrates. Our findings have revealed novel structural insights into the binding of substrates to hNit2/ω-amidase. A catalytic triad and the loop residues 116-128 of hNit2 play an essential role in supporting the stability of the enzyme-substrate complex, resulting in the generation of the catalytic products. These observations are predicted to be of benefit in the design of new inhibitors or activators for research involving cancer and hyperammonemic diseases.
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Affiliation(s)
- Chin-Hsiang Chien
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
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Cooper AJL, Krasnikov BF, Pinto JT, Kung HF, Li J, Ploessl K. Comparative enzymology of (2S,4R)4-fluoroglutamine and (2S,4R)4-fluoroglutamate. Comp Biochem Physiol B Biochem Mol Biol 2012; 163:108-20. [PMID: 22613816 DOI: 10.1016/j.cbpb.2012.05.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 05/11/2012] [Accepted: 05/14/2012] [Indexed: 11/26/2022]
Abstract
Many cancer cells have a strong requirement for glutamine. As an aid for understanding this phenomenon the (18)F-labeled 2S,4R stereoisomer of 4-fluoroglutamine [(2S,4R)4-FGln] was previously developed for in vivo positron emission tomography (PET). In the present work, comparative enzymological studies of unlabeled (2S,4R)4-FGln and its deamidated product (2S,4R)4-FGlu were conducted as an adjunct to these PET studies. Our findings are as follows: Rat kidney preparations catalyze the deamidation of (2S,4R)4-FGln. (2,4R)4-FGln and (2S,4R)4-FGlu are substrates of various aminotransferases. (2S,4R)4-FGlu is a substrate of glutamate dehydrogenase, but not of sheep brain glutamine synthetase. The compound is, however, a strong inhibitor of this enzyme. Rat liver cytosolic fractions catalyze a γ-elimination reaction with (2S,4R)4-FGlu, generating α-ketoglutarate. Coupling of a deamidase reaction with this γ-elimination reaction provides an explanation for the previous detection of (18)F(-) in tumors exposed to [(18)F](2S,4R)4-FGln. One enzyme contributing to this reaction was identified as alanine aminotransferase, which catalyzes competing γ-elimination and aminotransferase reactions with (2S,4R)4-FGlu. This appears to be the first description of an aminotransferase catalyzing a γ-elimination reaction. The present results demonstrate that (2S,4R)4-FGln and (2S,4R)4-FGlu are useful analogues for comparative studies of various glutamine- and glutamate-utilizing enzymes in normal and cancerous mammalian tissues, and suggest that tumors may metabolize (2S,4R)4-FGln in a generally similar fashion to glutamine. In plants, yeast and bacteria a major route for ammonia assimilation involves the consecutive action of glutamate synthase plus glutamine synthetase (glutamate synthase cycle). It is suggested that (2S,4R)4-FGln and (2S,4R)4-FGlu will be useful probes in studies of ammonia assimilation by the glutamate synthase pathway in these organisms. Finally, glutamine transaminases are conserved in mammals, plants and bacteria, and probably serve to close the methionine salvage pathway, thus linking nitrogen metabolism to sulfur metabolism and one-carbon metabolism. It is suggested that (2S,4R)4-FGln may be useful in studies of the methionine salvage pathway in a variety of organisms.
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Affiliation(s)
- Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA.
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Abstract
Transglutaminases catalyze the formation of γ-glutamylamines utilizing glutamyl residues and amine-bearing compounds such as lysyl residues and polyamines. These γ-glutamylamines can be released from proteins by proteases in an intact form. The free γ-glutamylamines can be catabolized to 5-oxo-L-proline and the free amine by γ-glutamylamine cyclotransferase. Free γ-glutamylamines, however, accumulate in the CSF and affected areas of Huntington Disease brain. This observation suggests transglutaminase-derived γ-glutamylamines may play a more significant role in neurodegeneration than previously thought. The following monograph reviews the metabolism of γ-glutamylamines and examines the possibility that these species contribute to neurodegeneration.
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Affiliation(s)
- Thomas M Jeitner
- Neurosciences, Biomedical Research Core, Winthrop University Hospital, 222 Station Plaza North, Mineola, USA.
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Bridges CC, Krasnikov BF, Joshee L, Pinto JT, Hallen A, Li J, Zalups RK, Cooper AJL. New insights into the metabolism of organomercury compounds: mercury-containing cysteine S-conjugates are substrates of human glutamine transaminase K and potent inactivators of cystathionine γ-lyase. Arch Biochem Biophys 2011; 517:20-9. [PMID: 22093698 DOI: 10.1016/j.abb.2011.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 11/26/2022]
Abstract
Anthropogenic practices and recycling in the environment through natural processes result in release of potentially harmful levels of mercury into the biosphere. Mercury, especially organic forms, accumulates in the food chain. Mercury reacts readily with sulfur-containing compounds and often exists as a thiol S-conjugate, such as the l-cysteine (Cys)-S-conjugate of methylmercury (CH(3)Hg-S-Cys) or inorganic mercury (Cys-S-Hg-S-Cys). These S-conjugates are structurally similar to l-methionine and l-cystine/l-cystathionine, respectively. Bovine and rat glutamine transaminase K (GTK) catalyze transamination of sulfur-containing amino acids. Recombinant human GTK (rhGTK) has a relatively open catalytic active site, and we report here that this enzyme, like the rat and bovine enzymes, can also utilize sulfur-containing l-amino acids, including l-methionine, l-cystine, and l-cystathionine as substrates. The current study extends this list to include mercuric S-conjugates, and shows that CH(3)Hg-S-Cys and Cys-S-Hg-S-Cys are substrates and reversible inhibitors of rhGTK. The homocysteine S-conjugates, Hcy-S-Hg-S-Hcy and CH(3)Hg-S-Hcy, are also inhibitors. Finally, we show that HgCl(2), CH(3)Hg-S-Cys and Cys-S-Hg-S-Cys are potent irreversible inhibitors of rat cystathionine γ-lyase. The present study broadens our knowledge of the biochemistry of mercury compounds by showing that Cys S-conjugates of mercury interact with enzymes that catalyze transformations of biologically important sulfur-containing amino acids.
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Affiliation(s)
- Christy C Bridges
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, GA 31207, USA
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Hallen A, Cooper AJL, Jamie JF, Haynes PA, Willows RD. Mammalian forebrain ketimine reductase identified as μ-crystallin; potential regulation by thyroid hormones. J Neurochem 2011; 118:379-87. [PMID: 21332720 DOI: 10.1111/j.1471-4159.2011.07220.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ketimine reductase (E.C. 1.5.1.25) was purified to apparent homogeneity from lamb forebrain by means of a rapid multi-step chromatography protocol. The purified enzyme was identified by MS/MS (mass spectrometry) as μ-crystallin. The identity was confirmed by heterologously expressing human μ-crystallin in Escherichia coli and subsequent chromatographic purification of the protein. The purified human μ-crystallin was confirmed to have ketimine reductase activity with a maximum specific activity similar to that of native ovine ketimine reductase, and was found to catalyse a sequential reaction. The enzyme substrates are putative neuromodulator/transmitters. The thyroid hormone 3,5,3'-l-triiodothyronine (T3) was found to be a strong reversible competitive inhibitor, and may have a novel role in regulating their concentrations. μ-Crystallin is also involved in intracellular T3 storage and transport. This research is the first to demonstrate an enzyme function for μ-crystallin. This newly demonstrated enzymatic activity identifies a new role for thyroid hormones in regulating mammalian amino acid metabolism, and a possible reciprocal role of enzyme activity regulating bioavailability of intracellular T3.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, New South Wales, Australia
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