Evidence for a new pathway in the microbial conversion of 3β-acetoxycholest-5-en-19-ol into estrone
Abstract
Incubation of 3β-acetoxycholest-5-en-19-ol 1 with Moraxella sp. gave three neutral metabolites 19-hydroxy-5α-androst-1-ene-3,17-dione 3, 19-hydroxyandrost-4-ene-3,17-dione 4 and 9α,19-dihydroxyandrost-4-en-3,17-dione 5 besides estrone 2. Hitherto, the metabolite 3 was unknown. Acidic metabolites were not formed. Time course, resting cell and cell-free experiments clearly suggest: (a) complete removal of the C17 side chain takes place prior to the aromatisation of A ring in 2. (b) The noninvolvement of C22 phenolic acids as intermediates in the degradative sequence from 1 to 2. (c) Partially purified steroid 1,2-dehydrogenase readily converts the neutral metabolite 4 into estrone 2 and formaldehyde in the presence of phenazine methosulfate, an artificial electron acceptor.