title: Stereoselective Reduction of Ethyl 4-Chloro-3-Oxobutanoate by a Microbial Aldehyde Reductase in an Organic Solvent-Water Diphasic System.
abstract: Enzyme-catalyzed asymmetric reduction of ethyl 4-chloro-3-oxobutanoate in an organic solvent-water diphasic system was studied. NADPH-dependent aldehyde reductase isolated from Sporobolomyces salmonicolor AKU4429 and glucose dehydrogenase were used as catalysts for reduction of ethyl 4-chloro-3-oxobutanoate and recycling of NADPH, respectively, in this system. In an aqueous system, the substrate was unstable. Inhibition of the reaction and inactivation of the enzymes by the substrate and the product were also observed. An n-butyl acetate-water diphasic system very efficiently overcame these limitations. In a 1,600-ml-1,600-ml scale diphasic reaction, ethyl (R)-4-chloro-3-hydroxybutanoate (0.80 mol; 86% enantiomeric excess) was produced from the corresponding oxoester in a molar yield of 95.4% with an NADPH turnover of 5,500 mol/mol.
authors.affiliation: Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606, and Biochemistry Department, Research Center, Denki Kagaku Kogyo, Machida, Tokyo 194, Japan.
authors.forename: Sakayu
authors.initials: S
authors.lastname: Shimizu
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kataoka
authors.forename: Masaaki
authors.initials: M
authors.lastname: Katoh
authors.forename: Tadashi
authors.initials: T
authors.lastname: Morikawa
authors.forename: Teruzo
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yamada