title: Characterization of 7-alpha-dehydroxylase in Clostridium leptum.
abstract: 7-alpha-Dehydroxylation of primary bile acids was demonstrated radiochromatographically in whole cells of Clostridium leptum but was not observed in intestinal Bacteroides species. Activity of 7-alpha-Dehydroxylase was detected within a pH range of 5 to 9 and was 8-fold higher in specific activity in cell cultures in the presence of 0.1 mM sodium cholate than in its absence. 7-alpha-Dehydroxylase activity in whole cells was markedly inhibitied by 2,4-dinitrophenol, carbonyl-cyanide-m-chlorophenylhydrazine, and dicyclohexylcarbodiimide. A hypothesis concerning the dietary regulation of 7-alpha-dehydroxylating intestinal anaerobic bacteria is presented.
mesh_terms: D001439:Bacteroides / Q000201:enzymology; D001647:Bile Acids and Salts; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D003013:Clostridium / Q000201:enzymology*; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D013250:Steroid Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D001647:Bile Acids and Salts; D004024:Dicyclohexylcarbodiimide; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D013250:Steroid Hydroxylases