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Takayasu S, Kamba A, Yoshida K, Terui K, Watanuki Y, Ishigame N, Mizushiri S, Tomita T, Nakamura K, Yasui-Furukori N, Daimon M. Secondary oxalosis induced by xylitol concurrent with lithium-induced nephrogenic diabetes insipidus: a case report. BMC Nephrol 2020; 21:157. [PMID: 32357847 PMCID: PMC7195762 DOI: 10.1186/s12882-020-01814-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 04/16/2020] [Indexed: 12/04/2022] Open
Abstract
Background Xylitol is an approved food additive that is widely used as a sweetener in many manufactured products. It is also used in pharmaceuticals. Secondary oxalosis resulting from high dietary oxalate has been reported. However, reported cases of oxalosis following xylitol infusion are rare. Case presentation A 39-year-old man with a 16-year history of organic psychiatric disorder was hospitalized for a laparoscopic cholecystectomy because of cholecystolithiasis. He had been treated with several antipsychotics and mood stabilizers, including lithium. The patient had polyuria (> 4000 mL/day) and his serum sodium levels ranged from 150 to 160 mmol/L. Urine osmolality was 141 mOsm/L, while serum arginine vasopressin level was 6.4 pg/mL. The patient was diagnosed with nephrogenic diabetes insipidus (NDI), and lithium was gradually discontinued. Postoperative urine volumes increased further to a maximum of 10,000 mL/day, and up to 10,000 mL/day of 5% xylitol was administered. The patient’s consciousness level declined and serum creatinine increased to 4.74 mg/dL. This was followed by coma and metabolic acidosis. After continuous venous hemodiafiltration, serum sodium improved to the upper 140 mmol/L range and serum creatinine decreased to 1.25 mg/dL at discharge. However, polyuria and polydipsia of approximately 4000 mL/day persisted. Renal biopsy showed oxalate crystals and decreased expression of aquaporin-2 (AQP2) in the renal tubules. Urinary AQP2 was undetected. The patient was discharged on day 82 after admission. Conclusions Our patient was diagnosed with lithium-induced NDI and secondary oxalosis induced by excess xylitol infusion. NDI became apparent perioperatively because of fasting, and an overdose of xylitol infusion led to cerebrorenal oxalosis. Our patient received a maximum xylitol dose of 500 g/day and a total dose of 2925 g. Patients receiving lithium therapy must be closely monitored during the perioperative period, and rehydration therapy using xylitol infusion should be avoided in such cases.
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Affiliation(s)
- Shinobu Takayasu
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
| | - Aya Kamba
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Kazutaka Yoshida
- Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Ken Terui
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Yutaka Watanuki
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Noriko Ishigame
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Satoru Mizushiri
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Tetsu Tomita
- Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Kazuhiko Nakamura
- Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Norio Yasui-Furukori
- Department of Neuropsychiatry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Shimotsuga, Tochigi, 321-0293, Japan
| | - Makoto Daimon
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine and Hospital, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
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Sabatino JA, Starin D, Tuchman S, Ferreira C, Regier DS. Elevated urine oxalate and renal calculi in a classic galactosemia patient on soy-based formula. JIMD Rep 2019; 49:7-10. [PMID: 31497475 PMCID: PMC6718118 DOI: 10.1002/jmd2.12056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/11/2019] [Accepted: 05/23/2019] [Indexed: 11/15/2022] Open
Abstract
Classic galactosemia results from a deficiency in the galactose-1-phosphate uridylyltransferase (GALT) enzyme, which is essential for galactose metabolism. Treatment focuses on lactose restriction and is achieved with a soy-based diet. Previously, renal calculi have not been documented in galactosemia patients. We present a patient with galactosemia nutritionally dependent on soy-based formula via G-tube, who developed renal calculi. Analysis of urinary stone risk factors revealed elevated urine oxalate levels and stone analysis confirmed calcium oxalate composition. Initiation of lactose- and soy-free elemental formula returned urine oxalate level to normal. Given the presence of a metabolic pathway for the conversion of galactose to oxalate, and the high content of oxalate in soy-based formula, there is the potential for elevated urine oxalate and a resulting risk of urinary calculi formation in patients with classic galactosemia. This potential can be effectively managed with a lactose and soy-free elemental diet. This report describes the clinical course and novel findings of calcium oxalate urinary calculi in a classic galactosemia patient dependent upon soy-based formula, with a discussion regarding the multiple factors leading to increased stone formation in this patient.
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Affiliation(s)
- Julia A. Sabatino
- Genetics and MetabolismRare Disease Institute, Children's National Medical CenterWashingtonDistrict of Columbia
| | - Danielle Starin
- Genetics and MetabolismRare Disease Institute, Children's National Medical CenterWashingtonDistrict of Columbia
| | - Shamir Tuchman
- Department of NephrologyChildren's National Medical CenterWashingtonDistrict of Columbia
| | - Carlos Ferreira
- National Human Genome Research Institute, National Institutes of HealthBethesdaMaryland
| | - Debra S. Regier
- Genetics and MetabolismRare Disease Institute, Children's National Medical CenterWashingtonDistrict of Columbia
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Cam Y, Alkim C, Trichez D, Trebosc V, Vax A, Bartolo F, Besse P, François JM, Walther T. Engineering of a Synthetic Metabolic Pathway for the Assimilation of (d)-Xylose into Value-Added Chemicals. ACS Synth Biol 2016; 5:607-18. [PMID: 26186096 DOI: 10.1021/acssynbio.5b00103] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A synthetic pathway for (d)-xylose assimilation was stoichiometrically evaluated and implemented in Escherichia coli strains. The pathway proceeds via isomerization of (d)-xylose to (d)-xylulose, phosphorylation of (d)-xylulose to obtain (d)-xylulose-1-phosphate (X1P), and aldolytic cleavage of the latter to yield glycolaldehyde and DHAP. Stoichiometric analyses showed that this pathway provides access to ethylene glycol with a theoretical molar yield of 1. Alternatively, both glycolaldehyde and DHAP can be converted to glycolic acid with a theoretical yield that is 20% higher than for the exclusive production of this acid via the glyoxylate shunt. Simultaneous expression of xylulose-1 kinase and X1P aldolase activities, provided by human ketohexokinase-C and human aldolase-B, respectively, restored growth of a (d)-xylulose-5-kinase mutant on xylose. This strain produced ethylene glycol as the major metabolic endproduct. Metabolic engineering provided strains that assimilated the entire C2 fraction into the central metabolism or that produced 4.3 g/L glycolic acid at a molar yield of 0.9 in shake flasks.
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Affiliation(s)
- Yvan Cam
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP),, 31077 Toulouse, France
- UMR5504, CNRS, 31077 Toulouse, France
- TWB, 3 rue des Satellites, Canal Biotech Building 2, 31400 Toulouse, France
| | - Ceren Alkim
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP),, 31077 Toulouse, France
- UMR5504, CNRS, 31077 Toulouse, France
- TWB, 3 rue des Satellites, Canal Biotech Building 2, 31400 Toulouse, France
| | - Debora Trichez
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP),, 31077 Toulouse, France
- UMR5504, CNRS, 31077 Toulouse, France
- TWB, 3 rue des Satellites, Canal Biotech Building 2, 31400 Toulouse, France
| | - Vincent Trebosc
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP),, 31077 Toulouse, France
- UMR5504, CNRS, 31077 Toulouse, France
- TWB, 3 rue des Satellites, Canal Biotech Building 2, 31400 Toulouse, France
| | - Amélie Vax
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP),, 31077 Toulouse, France
- UMR5504, CNRS, 31077 Toulouse, France
- TWB, 3 rue des Satellites, Canal Biotech Building 2, 31400 Toulouse, France
| | - François Bartolo
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- Département Génie Mathématiques et Modélisation (GMM), 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Philippe Besse
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- Département Génie Mathématiques et Modélisation (GMM), 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Jean Marie François
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP),, 31077 Toulouse, France
- UMR5504, CNRS, 31077 Toulouse, France
- TWB, 3 rue des Satellites, Canal Biotech Building 2, 31400 Toulouse, France
| | - Thomas Walther
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP),, 31077 Toulouse, France
- UMR5504, CNRS, 31077 Toulouse, France
- TWB, 3 rue des Satellites, Canal Biotech Building 2, 31400 Toulouse, France
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Diggle CP, Shires M, Leitch D, Brooke D, Carr IM, Markham AF, Hayward BE, Asipu A, Bonthron DT. Ketohexokinase: expression and localization of the principal fructose-metabolizing enzyme. J Histochem Cytochem 2009; 57:763-74. [PMID: 19365088 DOI: 10.1369/jhc.2009.953190] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Ketohexokinase (KHK, also known as fructokinase) initiates the pathway through which most dietary fructose is metabolized. Very little is known about the cellular localization of this enzyme. Alternatively spliced KHK-C and KHK-A mRNAs are known, but the existence of the KHK-A protein isoform has not been demonstrated in vivo. Using antibodies to KHK for immunohistochemistry and Western blotting of rodent tissues, including those from mouse knockouts, coupled with RT-PCR assays, we determined the distribution of the splice variants. The highly expressed KHK-C isoform localized to hepatocytes in the liver and to the straight segment of the proximal renal tubule. In both tissues, cytoplasmic and nuclear staining was observed. The KHK-A mRNA isoform was observed exclusively in a range of other tissues, and by Western blotting, the presence of endogenous immunoreactive KHK-A protein was shown for the first time, proving that the KHK-A mRNA is translated into KHK-A protein in vivo, and supporting the suggestion that this evolutionarily conserved isoform is physiologically functional. However, the low levels of KHK-A expression prevented its immunohistochemical localization within these tissues. Our results highlight that the use of in vivo biological controls (tissues from knockout animals) is required to distinguish genuine KHK immunoreactivity from experimental artifact.
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Affiliation(s)
- Christine P Diggle
- Leeds Institute of Molecular Medicine, University of Leeds, St James's University Hospital, Beckett Street, Leeds LS9 7TF, United Kingdom
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Mizutani H, Sako T, Toyoda Y, Fukuda H, Urumuhang N, Koyama H, Hirose H. The intravenous xylitol tolerance test in non-lactating cattle. Vet Res Commun 2003; 27:633-41. [PMID: 14672452 DOI: 10.1023/a:1027372429555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Xylitol is a five-carbon sugar alcohol that is often used for treatment of ketosis in dairy cattle in Japan. An intravenous xylitol tolerance test (IVXTT, 0.1 g/kg, bolus injection through the jugular vein) was performed in 4 non-lactating cows (n = 4) and the results were compared with those of an intravenous glucose tolerance test (IVGTT) performed under equivalent conditions. The serum xylitol concentration reached a peak value (41.4+/-9.0 mg/dl) at 5 min, and then rapidly decreased and almost disappeared within 2 h. The C0 for xylitol was 56.9+/-16.6 mg/dl and the t(1/2) was 8.5+/-0.9 min. The administration of xylitol appeared to cause similar secretion of insulin to that caused by glucose. There was also a reduction in the concentration of free fatty acids. It seems that xylitol has value for the treatment of ketosis. However, rapid administration of xylitol appeared to have an osmotic diuretic action and might be a cause of dehydration.
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Affiliation(s)
- H Mizutani
- Division of Veterinary Internal Medicine, Nippon Veterinary and Animal Science University, 1-7-1 Kyonanncho, Musashino, Tokyo 180-8602, Japan.
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Tonon FA, Kemmelmeier FS, Bracht A, Ishii-Iwamoto EL, Nascimento EA. Metabolic effects of oxalate in the perfused rat liver. Comp Biochem Physiol B Biochem Mol Biol 1998; 121:91-7. [PMID: 9972286 DOI: 10.1016/s0305-0491(98)10131-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of oxalate on the metabolism of the isolated perfused rat liver were investigated. The main purpose was to verify if oxalate is also active in intact organs as demonstrated in isolated cells. The results revealed that the action of oxalate in the perfused liver resembles only partially that observed in isolated hepatocytes. In the perfused liver, oxalate inhibited gluconeogenesis from alanine, pyruvate and lactate, inhibited glycolysis and stimulated glycogenolysis. These observations confirm previous measurements with isolated hepatocytes. However, additional effects, not observed in isolated hepatocytes, were found. In the perfused liver, oxalate stimulated glucose production from dihydroxyacetone, glycerol or sorbitol. Moreover, the effects of oxalate in the perfused rat liver occurred at concentrations well above those reported for isolated hepatocytes, revealing that the compound is less toxic in the intact tissue. In vivo, the metabolic effects reported here can only be expected to occur at supra-physiological concentrations of oxalate, as in the case of a chronic renal failure.
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Affiliation(s)
- F A Tonon
- Department of Biochemistry, University of Maringá, Brazil
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Salminen S, Salminen E, Bridges JW, Marks V. Intestinal absorption of oxalate by xylitol-treated rats and mice. Toxicol Lett 1988; 44:113-20. [PMID: 3188068 DOI: 10.1016/0378-4274(88)90137-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The absorption of 14C-labelled oxalic acid was studied in Wistar rats, CD-1 mice and NMRI mice. Oxalic acid in solution was given to the animals by gavage either with water alone or with 0.625 g/kg b.w. of xylitol. Both xylitol-adapted animals and animals not previously exposed to xylitol were used. Adaptation to xylitol diets enhanced the absorption and urinary excretion of the label (oxalic acid) in both strains of mice but not in rats. Earlier studies have indicated a high incidence of bladder calculi in mice but not in rats fed high amounts of xylitol. The results of the present study offer one likely explanation for the increased formation of bladder calculi as a result of oversaturation of urine with oxalate.
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Affiliation(s)
- S Salminen
- Department of Food Chemistry, University of Helsinki, Finland
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Arora KK, Smith R, Williams JF. "Pyruvate recycling" and its influence on the estimation of the pentose pathway in intact liver and Morris hepatoma 5123TC cells. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1987; 19:147-58. [PMID: 3569643 DOI: 10.1016/0020-711x(87)90325-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The phenomenon of "pyruvate recycling" is demonstrated in perfused rat liver, rabbit liver in situ and in Morris Hepatoma 5123TC cells and quantitatively measured using [2-14C]pyruvate and the method of Friedmann et al. (1971). Various metabolites, viz. lactate, DHAP, glucose, glucose 6-P and fructose 6-P were isolated and degraded following the metabolism of [2-14C]pyruvate and [2-14C]glycerol in order to assess the 14C-distributions imparted by "pyruvate recycling" reactions. The labelling of DHAP, lactate, glucose and glucose 6-P showed 14C randomizations consistent with the operation and the quantitative extent of "pyruvate recycling". These findings support the proposal that the actions of "pyruvate recycling" may account for the failure to find significant levels of 14C isotope at C-1 of glucose 6-P following the metabolism of [4,5,6-14C]- or [6-14C]glucose by L-type pentose pathway metabolism in aerobic intact tissues. "Pyruvate recycling" diminishes the measured value of the L-type pentose cycle in intact tissues and qualifies one of the mechanistic predictions of the L-type pentose pathway which was unravelled by tracing its reactions with labelled ribose 5-P and liver enzymes (Horecker et al., 1954; Williams et al., 1978a,b) in vitro. The demonstration of an association of L-type pentose pathway reactions with "pyruvate recycling" by way of the common reactions of their triose-P intermediates qualifies the superficial acceptance of the predictions of the L-type pathway in vitro for the distribution of isotopic labels by aerobic tissues in vivo.
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Williams JF, Arora KK, Longenecker JP. The pentose pathway: a random harvest. Impediments which oppose acceptance of the classical (F-type) pentose cycle for liver, some neoplasms and photosynthetic tissue. The case for the L-type pentose pathway. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1987; 19:749-817. [PMID: 3319734 DOI: 10.1016/0020-711x(87)90239-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- J F Williams
- Department of Biochemistry, Faculty of Science, Australian National University, Canberra
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Rofe AM, James HM, Bais R, Conyers RA. Hepatic oxalate production: the role of hydroxypyruvate. BIOCHEMICAL MEDICINE AND METABOLIC BIOLOGY 1986; 36:141-50. [PMID: 3778681 DOI: 10.1016/0885-4505(86)90118-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The metabolism of hydroxypyruvate to oxalate was studied in isolated rat hepatocytes. [14C]Oxalate was produced from [2-14C]- and [3-14C]- but not [1-14C]hydroxypyruvate. No oxalate was produced from similarly labeled pyruvate. The mechanism by which hydroxypyruvate is metabolized to oxalate involves decarboxylation at the carbon 1 position as the initial step. This activity was distinct from that which produced CO2 from the carbon 1 position of pyruvate. Hydroxypyruvate decarboxylase activity was found mainly in the mitochondria, with the remainder (25%) in the cytosol. No activity was present in the peroxisomes, the probable site of oxalate production from glycolate and glyoxylate. Hydroxypyruvate, but not pyruvate stimulated [14C]oxalate production from [U-14C]fructose, suggesting that hydroxypyruvate is either an intermediate in the fructose-oxalate pathway, or that it prevents carbon from leaving that pathway. The lack of effect of pyruvate in this regard is evidence against redox being the primary effect of hydroxypyruvate and focuses attention on hydroxypyruvate and its precursors as important sources of carbon for oxalate synthesis from both carbohydrate and protein.
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Bais R, James HM, Rofe AM, Conyers RA. The purification and properties of human liver ketohexokinase. A role for ketohexokinase and fructose-bisphosphate aldolase in the metabolic production of oxalate from xylitol. Biochem J 1985; 230:53-60. [PMID: 2996495 PMCID: PMC1152585 DOI: 10.1042/bj2300053] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Ketohexokinase (EC 2.7.1.3) was purified to homogeneity from human liver, and fructose-bisphosphate aldolase (EC 4.1.2.13) was partially purified from the same source. Ketohexokinase was shown, by column chromatography and polyacrylamide-gel electrophoresis, to be a dimer of Mr 75000. Inhibition studies with p-chloromercuribenzoate and N-ethylmaleimide indicate that ketohexokinase contains thiol groups, which are required for full activity. With D-xylulose as substrate, ketohexokinase and aldolase can catalyse a reaction sequence which forms glycolaldehyde, a known precursor of oxalate. The distribution of both enzymes in human tissues indicates that this reaction sequence occurs mainly in the liver, to a lesser extent in the kidney, and very little in heart, brain and muscle. The kinetic properties of ketohexokinase show that this enzyme can phosphorylate D-xylulose as readily as D-fructose, except that higher concentrations of D-xylulose are required. The kinetic properties of aldolase show that the enzyme has a higher affinity for D-xylulose 1-phosphate than for D-fructose 1-phosphate. These findings support a role for ketohexokinase and aldolase in the formation of glycolaldehyde. The effect of various metabolites on the activity of the two enzymes was tested to determine the conditions that favour the formation of glycolaldehyde from xylitol. The results indicate that few of these metabolites affect the activity of ketohexokinase, but that aldolase can be inhibited by several phosphorylated compounds. This work suggests that, although the formation of oxalate from xylitol is normally a minor pathway, under certain conditions of increased xylitol metabolism oxalate production can become significant and may result in oxalosis.
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References. Mol Aspects Med 1984. [DOI: 10.1016/b978-0-08-033239-0.50013-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Nath R, Thind SK, Murthy MS, Talwar HS, Farooqui S. Molecular aspects of idiopathic urolithiasis. Mol Aspects Med 1984; 7:1-176. [PMID: 6376994 DOI: 10.1016/0098-2997(84)90004-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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