Stereochemistry of the epoxidation of fatty acids catalyzed by soybean peroxygenase.

The stereochemistry of C18 unsaturated fatty acids epoxidation catalyzed by detergent-solubilized and partially purified soybean peroxygenase was determined by chiral phase HPLC. Linoleic acid was oxidized into 9, 10- and 12,13-cis-epoxyoctadecenoic acids with a high enantiofacial selectivity. A 5.2:1 and 2.3:1 ratio respectively in favor of the 9(R), 10(S)- and 12(R), 13(S)-epoxy enantiomers was observed. These epoxy-derivatives of linoleic acid have the chirality of metabolites known to be involved in plant defense against fungi. This finding is of importance in establishing a physiological role for the peroxygenase.