title: Cofactor requirements of steroid-17-20-desmolase and 20 alpha-hydroxysteroid dehydrogenase activities in cell extracts of Clostridium scindens.
abstract: Two neutral steroid-transforming activities were demonstrated in cell extracts of Clostridium scindens. Steroid-17-20-desmolase and 20 alpha-hydroxysteroid dehydrogenase were found to be inducible in cells cultured in the presence of cortisol. Both activities required manganese ions and NAD+ or NADH for activity. Cortisol, cortisone and 11-desoxycortisol were substrates as well as inducers of steroid-17-20-desmolase and 20 alpha-hydroxysteroid dehydrogenase activities. 17 alpha-Hydroxyprogesterone was an effective inducer but did not serve as a substrate for either enzyme activity. C. scindens is the first bacterial species of the normal human intestinal flora reported to elaborate inducible steroid-17-20-desmolase and 20 alpha-hydroxysteroid dehydrogenase activities. The results of cofactor, substrate specificity and induction studies suggest that these two activities may reside in the same enzyme complex.
mesh_terms: D015089:20-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D043607:20-alpha-Hydroxysteroid Dehydrogenase; D000446:Aldehyde-Lyases / Q000378:metabolism*; D002413:Cations, Divalent; D003013:Clostridium / Q000201:enzymology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D007700:Kinetics; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D013254:Steroid 17-alpha-Hydroxylase
chemical_list: D002413:Cations, Divalent; D009243:NAD; D003577:Cytochrome P-450 Enzyme System; D015089:20-Hydroxysteroid Dehydrogenases; D043607:20-alpha-Hydroxysteroid Dehydrogenase; D013254:Steroid 17-alpha-Hydroxylase; D000446:Aldehyde-Lyases