title: 3 beta-Hydroxysteroid dehydrogenase of Ruminococcus sp. from human intestinal bacteria.
abstract: Ruminococcus sp. PO1-3 obtained from human intestinal flora is able to reduce dehydrocholate as well as 3-ketoglycyrrhetinate. From this bacterium dehydrocholate- and 3-ketoglycyrrhetinate-reducing activities were purified one thousand-fold together with 3-ketocholanate-reducing and 3-beta-hydroxyglycyrrhetinate (glycyrrhetic acid) oxidizing activities by means of Matrex Red A, Sephadex G-200 and Octyl-Sepharose column chromatography. The purified enzyme catalyzed the reduction of dehydrocholic acid to 3 beta-hydroxy-7,12-diketocholanic acid and of 3-ketocholanic acid to 3 beta-hydroxycholanic acid. Studies on substrate specificity revealed that the enzyme had absolute specificity for the beta-configuration of a hydroxyl group at the 3 position of bile acid and steroids having no double bond in the A/B ring. This enzyme was neither beta-hydroxysteroid dehydrogenase [EC 1.1.1.51] nor 3 beta-hydroxy-delta 5-steroid dehydrogenase [EC 1.1.1.145], but a novel type of enzyme, defined as 3 beta-hydroxysteroid dehydrogenase.
authors.forename: T
authors.initials: T
authors.lastname: Akao
authors.forename: T
authors.initials: T
authors.lastname: Akao
authors.forename: M
authors.initials: M
authors.lastname: Hattori
authors.forename: T
authors.initials: T
authors.lastname: Namba
authors.forename: K
authors.initials: K
authors.lastname: Kobashi
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000302:isolation & purification* / Q000378:metabolism; D002384:Catalysis; D002850:Chromatography, Gel; D002855:Chromatography, Thin Layer; D003685:Dehydrocholic Acid / Q000378:metabolism; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D010084:Oxidation-Reduction; D010459:Peptococcaceae / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D015096:3-Hydroxysteroid Dehydrogenases; D003685:Dehydrocholic Acid