| abstract |
From lactobacilli, in particular from lactobacillus kefir, a phenylethanol dehydrogenase capable of reducing acetophenone to R (+) - phenylethanol in the presence of NADPH is isolated. This is in addition to the reduction of aromatic, alicyclic and aliphatic ketones, such as in particular p-bromo-acetophenone, methylcyclohexanone, acetone, methyl hexyl ketone, 4-phenyl-2-butanone, 1-phenyl-1,2-propanedione, ethyl pentyl ketone, pinacoline , Propiophenone, p-chloro-acetophenone. EDTA rapidly deactivates it, but conventional inhibitors, chelators and SH protective reagents have only a minor influence on the activity. The K M value for acetophenone is 6 x 10⁻⁴ M. The dehydrogenase is suitable for the enzymatic reduction of oxo compounds to form optically active hydroxy compounds in the presence of NADPH, preferably with simultaneous regeneration of NADPH within the reaction mixture , in particular by means of glucose-6-P / gluxose-6-P-dehydrogenase or isopropanol. |