title: Purification and characterization of a new hydrolase for conjugated bile acids, chenodeoxycholyltaurine hydrolase, from Bacteroides vulgatus.
abstract: A new hydrolase for conjugated bile acids, tentatively named chenodeoxycholyltaurine hydrolase, was purified to homogeneity from Bacteroides vulgatus. This enzyme hydrolyzed taurine-conjugated bile acids but showed no activity toward glycine conjugates. Among the taurine conjugates, taurochenodeoxycholic acid was most effectively hydrolyzed, tauro-beta-muricholic and ursodeoxycholic acids were moderately well hydrolyzed, and cholic and 7 beta-cholic acids were hardly hydrolyzed, suggesting that this enzyme has a specificity for not only the amino acid moiety but also the steroidal moiety. The molecular weight of the enzyme was estimated to be approximately 140,000 by Sephacryl S-300 gel filtration and the subunit molecular weight of the enzyme was 36,000 by SDS-polyacrylamide gel electrophoresis. The optimum pH was in the range of 5.6 to 6.4. The NH2-terminal amino acid sequence of the enzyme was Met-Glu-Arg-Thr-Ile-Thr-Ile-Gln-Gln-Ile-Lys-Asp-Ala-Ala-Gln. The enzyme was activated by dithiothreitol, but inhibited by sulfhydryl inhibitors, p-hydroxymercuribenzoate, N-ethylmaleimide, and dithiodipyridine.
authors.affiliation: Shionogi Research Laboratories, Osaka.
authors.forename: K
authors.initials: K
authors.lastname: Kawamoto
authors.forename: I
authors.initials: I
authors.lastname: Horibe
authors.forename: K
authors.initials: K
authors.lastname: Uchida
mesh_terms: D000581:Amidohydrolases / Q000302:isolation & purification* / Q000378:metabolism; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001439:Bacteroides / Q000201:enzymology*; D001647:Bile Acids and Salts / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013655:Taurochenodeoxycholic Acid / Q000378:metabolism
chemical_list: D000596:Amino Acids; D001647:Bile Acids and Salts; D013439:Sulfhydryl Reagents; D013655:Taurochenodeoxycholic Acid; D000581:Amidohydrolases; C063262:chenodeoxycholyltaurine hydrolase