Coenzyme specificity of mammalian liver d-glycerate dehydrogenase
Article first published online: 3 MAR 2005
European Journal of Biochemistry
Volume 186, Issue 1-2, pages 355–359, December 1989
How to Cite
Van SCHAFTINGEN, E., DRAYE, J.-P. and Van HOOF, F. (1989), Coenzyme specificity of mammalian liver d-glycerate dehydrogenase. European Journal of Biochemistry, 186: 355–359. doi: 10.1111/j.1432-1033.1989.tb15216.x
- Issue published online: 3 MAR 2005
- Article first published online: 3 MAR 2005
- (Received May 18/August 22, 1989) – EJB 89 0632
d-Glycerate dehydrogenase (glyoxylate reductase) was partially purified from rat liver by anion- and cation-exchange chromatography. When assayed in the direction of d-glycerate or glycolate formation, the enzyme was inhibited by high (≥0.5 mM), unphysiological concentrations of hydroxypyruvate or glyoxylate much more potently in the presence of NADPH than in the presence of NADH. However, the dehydrogenase displayed a much greater affinity for NADPH (Km < 1 μM) than for NADH (Km= 48–153 μM). Furthermore, NADP was over 1000-fold more potent than NAD in inhibiting the enzyme competitively with respect to NADH. NADP also inhibited the reaction competitively with respect to NADPH whereas NAD, at concentrations of up to 10 mM had no inhibitory effect. When measured by the formation of hydroxypyruvate from d-glycerate, the enzyme also displayed a much greater affinity for NADP than for NAD. These properties indicate that liver d-glycerate dehydrogenase functions physiologically as an NADPH-specific reductase.
In agreement with this conclusion, the addition of hydroxypyruvate or glyoxylate to suspensions of rat hepatocytes stimulated the pentose-phosphate pathway. The coenzyme specificity of d-glycerate dehydrogenase is discussed in relation to the biochemical findings made in d-glyceric aciduria and in primary hyperoxaluria type II (l-glyceric aciduria).