A kinetic study and application of a novel carbonyl reductase isolated from Rhodococcus erythropolis

The newly described carbonyl reductase from Rhodococcus erythropolis (RECR) accepts a broad range of substrates. Based on the kinetic constants of a variety of methyl and ethyl ketones a hypothetical model of the substrate-binding site is proposed. Whether a substrate of interest may be reduced by the RECR can be predicted from this model together with the kinetic data. A study of initial velocities and product inhibition is presented, which shows that the kinetics of the RECR follow a Theorell-Chance mechanism. The pro-R hydride of NADH is transferred by the enzyme to the re face of the carbonyl compounds yielding (S)-alcohols. The reduction of methyl 3-oxobutanoate and ethyl 4-chloro-3-oxobutanoate catalyzed by the oxidoreductase lead to the corresponding hydroxy compounds with high enantiomeric purity [enantiomeric excess (e.e.) > or = 99%]. The synthesis of ethyl (2R,3S)-3-hydroxy-2-methylbutanoate was accomplished with high diastereoselectivity (diastereomeric excess = 95%) and enantioselectivity (e.e. > or = 95%).