Overexpression and characterization of a novel (S)-specific extended short-chain dehydrogenase/reductase from Candida parapsilosis.

The gene encoding a putative protein from Candida parapsilosis CDC317 (CPE) was cloned and overexpressed in Escherichia coli. The protein was amenable to overexpression in E. coli and constituted 35% of the total cell protein content. The optimal activity was determined at pH 5.5 and 40°C with the substrate 4-chloro-3-oxobutanoate ethyl ester (COBE). The optical purity of the product was over 99% enantiomeric excess for the (S)-isomer, and the molar conversion yield of the product was 91.1%. The apparent k(m) value for COBE was 0.19±0.01mM, which is an order of magnitude lower than that of other enzymes in the literature.