Oxalate production from glyoxylate by lactate dehydrogenase in vitro: inhibition by reduced glutathione, cysteine, cysteamine.
Lactate dehydrogenase is known to act as a dismutase converting glyoxylate to oxalate and glycolate. LDH (sources: human erythrocytes, human plasma; rabbit muscle; rat liver) activity was assayed at 340 nm using glyoxylate (5.0 mmol/l) and NADH. The LDH activity (approx. % of control) in all the cases decreased respectively in the presence of 5.0 and 10.0 mmol/l of cysteine (45 and 20), cysteamine (45 and 20), and GSH (55 and 30). This decrease in LDH activity resulted in decreased oxalate production from glyoxylate (0.5 mmol/l). A 50% inhibition in oxalate production was observed in presence of 0.3 mmol/l cysteine, 0.35 mmol/l cysteamine, and 2.0 mmol/l GSH. The results suggest that the net LDH activity towards oxalate production may be regulated by the free SH-groups in the cell. This possibility needs evaluation as a tool to lower endogenous oxalate production and the associated risk of stone formation.
Sharma
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Department of Surgery, University of Erlangen, Germany.
Schwille
P O
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D000818:Animals; D003543:Cysteamine / Q000494:pharmacology*; D003545:Cysteine / Q000494:pharmacology*; D004229:Dithiothreitol / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology*; D006038:Glyoxylates / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D009124:Muscle Proteins / Q000378:metabolism; D010070:Oxalates / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D006038:Glyoxylates; D009124:Muscle Proteins; D010070:Oxalates; D013439:Sulfhydryl Reagents; D003543:Cysteamine; D007770:L-Lactate Dehydrogenase; D005978:Glutathione; D003545:Cysteine; D004229:Dithiothreitol