Primary hyperoxaluria type 2: enzymology.

Deficiency of the enzyme D-glycerate dehydrogenase (D-GDH) which also has glyoxylate reductase (GR) activity, is believed to be the underlying cause of primary hyperoxaluria type 2 (PH2). We have established the reaction kinetics of this enzyme in human liver and using these parameters have developed a microassay for the measurement of D-GDH and GR on needle liver biopsies obtained from patients with suspected primary hyperoxaluria. Tissue distribution studies of the two enzyme activities suggest that more than one enzyme with D-GDH activity is present in human tissues and the one with associated GR activity is mainly confined to the liver. The clinical significance of these findings for diagnosis and treatment is discussed.