Chiral alcohol production by NADH-dependent phenylacetaldehyde reductase coupled with in situ regeneration of NADH.

Nobuya Itoh, Michiko Matsuda, Mariko Mabuchi, Tohru Dairi, Jincun Wang

Index: Eur. J. Biochem. 269(9) , 2394-402, (2002)

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Abstract

Phenylacetaldehyde reductase (PAR) produced by styrene-assimilating Corynebacterium strain ST-10 was used to synthesize chiral alcohols. This enzyme with a broad substrate range reduced various prochiral aromatic ketones and beta-ketoesters to yield optically active secondary alcohols with an enantiomeric purity of more than 98% enantiomeric excess (e.e.). The Escherichia coli recombinant cells which expressed the par gene could efficiently produce important pharmaceutical intermediates; (R)-2-chloro-1-(3-chlorophenyl)ethanol (28 mg.mL-1) from m-chlorophenacyl chloride, ethyl (R)-4-chloro-3-hydroxy butanoate) (28 mg.mL-1) from ethyl 4-chloro-3-oxobutanoate and (S)-N-tert-butoxycarbonyl(Boc)-3-pyrrolidinol from N-Boc-3-pyrrolidinone (51 mg.mL-1), with more than 86% yields. The high yields were due to the fact that PAR could concomitantly reproduce NADH in the presence of 3-7% (v/v) 2-propanol in the reaction mixture. This biocatalytic process provided one of the best asymmetric reductions ever reported.