A novel enzyme system for the reduction of 3-oxo bile acids in human red blood cells.
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.
Goto
J
J
Faculty of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai, Japan.
Miura
H
H
Ando
M
M
Yamato
Y
Y
Ikegawa
S
S
Nambara
T
T
Makino
I
I
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
D001647:Bile Acids and Salts; D002793:Cholic Acids; D010103:Oxygen Isotopes; C017234:7,12-dihydroxy-3-oxocholanic acid; D003685:Dehydrocholic Acid