title: A novel enzyme system for the reduction of 3-oxo bile acids in human red blood cells.
abstract: 7 alpha,12 alpha-Dihydroxy-3-oxo- and 3,7,12-trioxo-5 beta-cholanoic acids labeled with 18O atoms were incubated with human red blood cells, and the biotransformation products were separated and characterized by gas chromatography-mass spectrometry as the pentafluorobenzyl ester-trimethylsilyl and -dimethylethylsilyl ether derivatives with the negative ion chemical ionization mode. The reduced products, 3 beta,7 alpha,12 alpha-trihydroxy-5 beta-cholanoic acid for the former, and 3 alpha-hydroxylated dioxo bile acid together with 3 beta-hydroxylated 7,12-dioxo-5 beta-cholanoic acid for the latter, were identified as metabolites. When 3-oxo bile acid was incubated with human blood denatured at 70 degrees C for 2 min, no metabolites were formed. The enzymic reduction activity has been localized in the red blood cell fraction.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Goto
authors.forename: H
authors.initials: H
authors.lastname: Miura
authors.forename: M
authors.initials: M
authors.lastname: Ando
authors.forename: Y
authors.initials: Y
authors.lastname: Yamato
authors.forename: S
authors.initials: S
authors.lastname: Ikegawa
authors.forename: T
authors.initials: T
authors.lastname: Nambara
authors.forename: I
authors.initials: I
authors.lastname: Makino
mesh_terms: D001647:Bile Acids and Salts / Q000737:chemistry / Q000378:metabolism*; D001711:Biotransformation; D001769:Blood / Q000378:metabolism*; D002793:Cholic Acids / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D002849:Chromatography, Gas; D003685:Dehydrocholic Acid / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010103:Oxygen Isotopes
chemical_list: D001647:Bile Acids and Salts; D002793:Cholic Acids; D010103:Oxygen Isotopes; C017234:7,12-dihydroxy-3-oxocholanic acid; D003685:Dehydrocholic Acid