Highly Enantioselective Reduction of Carbonyl Compounds Using a Reductase Purified from Bakers' Yeast

An NADPH-dependent reductase that shows reducing activity for 1-chloro-2-hexanone has been purified from bakers' yeast. SDS−PAGE and gel filtration suggested that the purified reductase is a monomeric enzyme with a molecular weight of ca. 37 kDa. Asymmetric reduction of several carbonyl compounds using the purified reductase has been carried out. 1-Chloro-2-hexanone, 1-acetoxy-2-heptanone, methyl acetoacetate, ethyl pyruvate, 1-chloro-2,4-pentanedione, and 2,4-hexanedione were reduced to the corresponding alcohols with high enantiomeric purities (>98% ee). The reductase showed high specificity constants ( k cat / K m = 10 3 −10 5 s - 1 M - 1 ) and relatively low Michaelis constants ( K m = 10 - 4 −10 - 3 M) for all the substrates examined.