Enantioselective inhibition: a strategy for improving the enantioselectivity of biocatalytic systems

Article abstract of DOI:10.1021/ja00199a053

Dextromethorphan (DM) and levomethorphan (LM) were found to be effective enantioselective inhibitors of Candida cylindracea lipase-catalyzed hydrolysis of a variety of (±)-arlypropionic and (±)-(arloxy)propionic esters. The enantioselectivity of the biocatalytic resolution of (±)-methyl 2-(2,4-dichlorophenoxy)propionate (DCPP) was enhanced 20-fold in the presence of either DM or LM. A general model for enantioselective inhibition has been developed, and a quantitative expression has been derived to show the underlying parameters that govern enantioselective inhibition. To define the mechanism of action of DM, a series of kinetic inhibition experiments was conducted with enantiomerically pure (R)-(+)-DCPP and (S)-(-)-DCPP. The observed inhibition pattern was that of partial noncompetitive inhibition for (R)-(+)-DCPP and that of pure noncompetitive inhibition for (S)-(-)-DCPP.