Kinetic investigation on enantioselective hydrolytic resolution of epichlorohydrin by crude epoxide hydrolase from domestic duck liver

Abstract

Enantiopure epichlorohydrin is a valuable epoxide intermediate for preparing optically active pharmaceuticals. In this study, a novel epoxide hydrolase prepared from domestic duck liver was used as biocatalyst for producing (S) - epichlorohydrin from its racemates. To characterize the biocatalytic profiles of crude epoxide hydrolase, some effect factors were investigated. The crude epoxide hydrolase has an apparent optimal pH of 8.0 and an optimal temperature of 35°C. Fe²⁺ and Mn²⁺ both enhanced the activity of epoxide hydrolase to different degrees. The results of kinetic study revealed that a significant inhibition phenomenon is observed in this reaction process. The apparent kinetic parameters (viz., V _max and K_m) and apparent substrate inhibition parameter K_is were calculated with linear fitting. The developed production process indicates that the novel epoxide hydrolase from domestic duck liver is a highly efficient biocatalyst for preparing enantiopure epichlorohydrin.

Key words: Epoxide hydrolase, enantiopure epichlorohydrin, enantioselective hydrolysis, kinetic resolution.