Stereospecificity of linoleic acid hydroperoxide isomerase from corn germ

Linoleic acid hydroperoxide isomerase from corn germ inverted the stereoconfiguration of its substrate. 9‐D(S)‐Hydroperoxy‐ trans ‐10, cis ‐12‐octadecadienoic acid was converted to 10‐oxo‐9‐L(R)‐hydroxy‐ cis ‐12‐octadecenoic acid. Presumably, the H 2 O solvent of OH − acted as a nucleophile. In the presence of another nucleophile, linoleate, the 9‐D(S)‐hydroperoxide was transformed into 9‐L(R)‐linoleoyloxy‐10‐oxo‐ cis ‐12‐octadecenoic acid. The substitution of nucleophiles from the incubation solution and the inversion of stereoconfiguration at carbon‐9 are consistent with a bimolecular nucleophilic substitution (S N 2) mechanism.