Mechanism of lipoxidase reaction. II. Origin of the oxygen incorporated into linoleate hydroperoxide.

Two different series of experiments were performed to establish the origin of the oxygen molecule incorporated into hydroperoxide during the incubation of lipoxidase with linoleic acid. These showed, as previously assumed but never demonstrated, that the oxygen introduced into the hydroperoxide molecules comes from the gaseous phase and not from the aqueous phase. Furthermore, soybean lipoxidase does not catalyze the exchange between gaseous oxygen and water oxygen. Possibly, lipoxidase may be involved in the biosynthesis of hydroxytrans,cis conjugated octadecadienoates present in various seeds.