MICROBIAL TRANSFORMATIONS OF STEROIDS .10. CYTOCHROMES P-450 11-ALPHA-HYDROXYLASE AND C17-C20 LYASE AND A 1-ENE DEHYDROGENASE TRANSFORM STEROIDS IN NECTRIA-HAEMATOCOCCA

Nectria haematococca contains four enzymes that metabolise exogenous s teroids. Two of these are microsomal cytochromes P-450 which act seque ntially on progesterone producing firstly, by side-chain cleavage, the C-19 steroid androstenedione (C17-C20 lyase), and then, in a subseque nt set of transformations, 11 alpha-hydroxylated derivatives (11 alpha -hydroxylase). Two other conversions occur after side-chain cleavage. Unsaturation, in the form of a double bond at C1-C2, is introduced int o the A ring by a catalytically self-sufficient microsomal 1-ene dehyd rogenase. This enzyme is specific for C-19 substrates. A C17-specific oxidoreductase is also involved in the production of androstenedione a nd testosterone from progesterone. The lyase, 11 alpha-hydroxylase and 1-ene dehydrogenase were purified to homogeneity. Copyright (C) 1996 Elsevier Science Ltd.