Involvement of a single hydroxylase species in the hydroxylation of palmitate at the omega-1, omega-2 and omega-3 positions by a preparation from Bacillus megaterium.

A soluble enzyme preparation from Bacillus megaterium, requiring NADPH and O2 for activity and containing ferredoxin-replaceable and cytochrome P-450-type components, was previously shown to catalyze the conversion of palmitic acid to an isomeric mixture of omega-1, omega-2 and omega-3 hydroxypalmitate. It has now been shown that the ratio of these three positional isomers in the enzymatic product remains unchanged in spite of partial diminution of total hydroxylase activity by heat treatment, pH change or inhibition by p-hydroxy-mercuribenzoate or carbon monoxide. These findings strongly support the hypothesis that a single hydroxylase with one substrate binding site is responsible for hydroxylation at all three positions of palmitate.