Microbial hydroxylations V. 11α-hydroxylation of progesterone by cell-free preparations of Aspergillus ochraceus

Abstract

The 11α-hydroxylation of progesterone and 19-nortestosterone by cell-free enzyme systems made from homogenates of vegetative cell cultures of Aspergillus ochraceus NRRL 405 is described. The 11α-hydroxylase is inducible and remains in the supernatant after centrifugation at 24000 × g. The 11α-hydroxylase induced by progesterone or by 19-nortestosterone is free from the associated 6β-hydroxylase or 17β-hydroxysteroid dehydrogenase activities of vegetative cell cultures of A. ochraceus NRRL 405, but induction with 11α-hydroxyprogesterone yields an enzyme preparation with both 6β- and 11β-hydroxylase activities. Although complete conversion of progesterone to 11α-hydroxyprogesterone was accomplished with the cell-free preparations, only 14% conversion of 19-nortestosterone to 11α-hydroxy-19-nortestosterone was possible.