Blee_1992_Biochem.Biophys.Res.Commun_187_171

Soybean epoxide hydrolase efficiently catalyzes the hydration of the two positional isomers of linoleic acid monoepoxides into their corresponding vic-diols. Kinetic analysis of the progress curves, obtained at low substrate concentrations (i.e. [So] much less than Km), and analysis of the residual substrates by chiral-phase HPLC, indicate that the hydrolase is highly enantioselective, i.e. cis-9R,10S-epoxy-12(Z)-octadecenoic and cis-12R,13S-epoxy-9(Z)-octadecenoic acids are preferentially hydrolyzed (the enantioselectivity ratios are 15 and 28, respectively). Importantly, these two enantiomers are the one formed preponderantly by epoxidation of linoleic acid by peroxygenase, a hydroperoxide-dependent oxidase we have previously described in soybean (Blee, E., and Schuber, F., Biochem. Biophys. Res. Commun. (1990) 173, 1354-1360).