Purification and characterization of glycerol 3-phosphate dehydrogenase from two types of acidiphilium sp

Acidiphilium sp. 63 and 24R, which were isolated from strongly and weakly acidic environments, grew well on glycerol. Both glycerol kinase and glycerol 3-phosphate dehydrogenase (G3PDH) were induced during growth on glycerol. After centrifugation of the crude extracts at 100, 000 × g for 60 min, the G3PDH activity in strain 63 was found in the precipitate, on the other hand, 80% of that in strain 24R was found in the supernatant. We solubilized the G3PDH from strains 63 and 24R with 0.1% Brij 58, and both enzymes were purified to homogeneity. When a detergent was removed from these enzymes with cold aqueous 90% acetone, the activities were reduced to 11% and 28%, and were restored to about 55% of the original activities on addition of 0.1% Brij 58. By sonication with phospholipid, the 63-G3PDH activity was restored very well. Both purified enzymes have a molecular weight of 108, 000 and their coenzymes were FAD. These enzymes from strain 63 and 24R had a Km of 0.38 and 1.3 mM for DL-glycerol 3-phosphate and the optimal pHs of these enzymes were 7.0 and 8.8, respectively.