title: Enzymes involved in the formation of 3 beta, 7 beta-dihydroxy-12-oxo-5 beta-cholanic acid from dehydrocholic acid by Ruminococcus sp. obtained from human intestine.
abstract: Ruminococcus sp. PO1-3 from human intestinal flora reduced dehydrocholic acid to 3 beta-hydroxy-7,12-dioxo-5 beta-cholanic acid by means of the enzyme 3 beta-hydroxysteroid dehydrogenase (Akao, T., Akao, T., Hattori, M., Namba, T. and Kobashi, K. (1986) J. Biochem. (Tokyo) 99, 1425-1431). This bacterium and its crude extract gave rise to another product, showing a lower RF value on TLC, from dehydrocholic acid. The product was identified as 3 beta, 7 beta-dihydroxy-12-oxo-5 beta-cholanic acid. The crude extract reduced 7-ketolithocholic acid and its methyl ester, but not 6-ketolithocholic acid and 12-ketochenodeoxycholic acid, in the presence of NADPH, and oxidized ursodeoxycholic acid and beta-muricholic acid, but not cholic acid, chenodeoxycholic acid, deoxycholic acid and hydrocholic acid, in the presence of NADP+. Therefore, besides 3 beta-hydroxysteroid dehydrogenase, 7 beta-hydroxysteroid dehydrogenase was shown to be present in this bacterium. The two dehydrogenases were clearly separated from each other by butyl-Toyopearl 650 M column chromatography. From dehydrocholic acid, 7 beta-hydroxy-3,12-dioxo-5 beta-cholanic acid was produced by 7 beta-hydroxysteroid dehydrogenase and 3 beta, 7 beta-dihydroxy-12-oxo-5 beta-cholanic acid was produced by combination of two enzymes, 7 beta- and 3 beta-hydroxysteroid dehydrogenase.
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*; D002635:Chenodeoxycholic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis; D002793:Cholic Acids / Q000378:metabolism; D002845:Chromatography; D003685:Dehydrocholic Acid / Q000378:metabolism*; D006801:Humans; D006913:Hydroxysteroid Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*; D007422:Intestines / Q000382:microbiology*; D009249:NADP / Q000494:pharmacology; D010459:Peptococcaceae / Q000201:enzymology*
chemical_list: D002793:Cholic Acids; D002635:Chenodeoxycholic Acid; C025576:3,7-dihydroxy-12-oxocholanoic acid; D009249:NADP; D015096:3-Hydroxysteroid Dehydrogenases; D006913:Hydroxysteroid Dehydrogenases; C031932:7 beta-hydroxysteroid dehydrogenase; D003685:Dehydrocholic Acid