Glycerol dehydrogenase and dihydroxyacetone reductase of a methylotrophic yeast, Hansenula ofunaensis.

Abstract

NAD+-Linked glycerol dehydrogenase (GDH) activity in Hansenula ofunaensis grown on glycerol was separated into three enzymes by a procedure involving DEAE-cellulose and DEAE-Sephadex A-50 column chromatographies. The oxidative activities toward glycerol of GDH I-1 and GDH I-2 were only detected when the concentration of glycerol was high, while GDH II showed significant activity with a low concentration of glycerol. The Km values for glycerol of GDH I-1, GDH I-2 and GDH II were 0.56M, 2.9M and 0.16M, respectively. The Km values for dihydroxyacetone of GDH I-1, GDH I-2 and GDH II were 0.40M, 0.36M and 1.7 mM, respectively. The oxidative activities toward 1, 2-propanediol of GDH I-1 and GDH II were 0.37- and 1.5-fold those toward glycerol, respectively. GDH I-2 showed significant oxidative activity toward ethanol, while GDH I-1 and GDH II showed no such activity. GDH I-2 was identical to dihydroxyacetone reductase induced in methanol-grown cells.