PARTIAL-PURIFICATION, SUBSTRATE-SPECIFICITY AND REGULATION OF ALPHA-L-GLYCEROLPHOSPHATE DEHYDROGENASE FROM SACCHAROMYCES-CARLSBERGENSIS

α-l-Glycerolphosphate dehydrogenase (sn-glycerol-3-phosphate:NAD+-2-oxidoreductase, EC 1.1.1.8) from Saccharomyces carlsbergensis was purified 400-fold. The enzyme preparation is free of interfering activities, such as glyceraldehyde phosphate dehydrogenase, alcohol dehydrogenase, triose phosphate isomerase and glycerolphosphatase. At pH 7.0 it is specific for NADH (Km=0.027 mM with 0.8 mM dihydroxyacetone phosphate) and dihydroxy-acetone phosphate (Km=0.2 mM with 0.2 mM NADH). Between pH 5.0 and 6.0 the enzyme functions with NADPH, but only at 7% of the rate with NADH. Various anions (I-> SO42-> Br->Cl-) act as inhibitors competing with the substrate dihydroxyacetone phosphate. Inorganic phosphate (Ki=0.1 mM), pyrophosphate and arsenate are strong inhibitors. The nucleotides ATP and ADP are also inhibitory, but their action seems to be of the same type as the general anion competition (Ki = 0.73 mM for ATP). The results are consistent with the notion that the enzyme may regulate the redox potential of the NAD+/NADH couple during fermentation. © 1979.