Oxidative side-chain and ring fission of pregnanes by Arthrobacter simplex.

Metabolic processes involving side-chain and ring cleavage of progesterone, 17-hydroxyprogesterone, 11-deoxycortisol and 16-dehydropregnenolone by Arthrobacter simplex were studied. The formation of the metabolites from progesterone indicates a pathway somewhat different from normal in the enzymic reaction sequence, and the 17-hydroxyprogesterone metabolites reveal a non-enzymic rearrangement step. The presence of a hydroxy group at C-21, as in 11-deoxycortisol, induces reduction of the C-20 carbonyl group. The microbial preparation of a novel androstane analogue, 17 beta-hydroxy-16 alpha-methoxyandrosta-1,4-dien-3-one, by incubation of 16-dehydropregnenolone with the bacterial strain was achieved. The formation of this metabolite is a multistep process involving a novel microbial generation of a methoxy group from a double-bond transformation in a steroid skeleton.