| 摘要 |
A phenylethanol dehydrogenase capable of catalyzing the reduction of acetophenone to R(+)-phenylethanol in the presence of NADPH was isolated from Lactobacilli such as Lactobacillus kefir. The dehydrogenase is also capable of catalyzing the reduction of aromatic, alicyclic and aliphatic ketones selected from the group consisting of p-bromoacetophenone, methylcyclohexanone, acetone, methyl hexyl ketone, 4-phenyl-2-butanone, 1-phenyl-1,2-propanedione, ethyl pentyl ketone, pinacolone, propiophenone and p-chloroacetophenone. The dehydrogenase is rapidly inactivated by EDTA, but conventional inhibitors, chelators and SH-protecting reagents have only a slight effect on activity. The enzyme has a KM of 6x10-4 M for acetophenone. The dehydrogenase is capable of catalyzing the enzymatic reduction of carbonyl compounds to form optically active hydroxy compounds in the presence of NADPH. In such reactions, NADPH can be simultaneously regenerated in the presence of glucose 6-P and glucose-6-P dehydrogenase or isopropanol. |
