Transformation of bile acids into iso-bile acids by Clostridium perfringens: possible transport of 3 beta-hydrogen via the coenzyme.
We have examined the mechanism for the bacterial transformation of chenodeoxycholic acid and lithocholic acid into the corresponding 3 beta-hydroxy epimers with the use of 3 alpha- and 3 beta-tritiated bile acids. The 3-oxo bile acids were transformed into the 3 alpha- (85%) and 3 beta- (15%) hydroxy bile acids after 20-hr incubation with Clostridium perfringens. Approximately 75% radioactivity was recovered in the aqueous medium when [3 beta-3H]chenodeoxycholic acid or [3 beta-3H]lithocholic acid was incubated with the bacteria, and approximately 15% of radioactivity in the bile acid fraction was associated with the 3 alpha-position of the iso-bile acids. When [3 beta-3H]chenodeoxycholic acid was incubated with unlabeled 3-oxo-5 beta-cholanoic acid, tritiated litho- and iso-lithocholic acids were recovered. These results can be explained only when a 3-oxo intermediate is postulated, and the 3 beta-hydrogen in the bile acids is transferred by the bacterial coenzyme (NAD+ or NADP+) to the 3 alpha-position in the iso-bile acids during the reduction of the 3-oxo compounds.
Batta
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Shefer
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D001647:Bile Acids and Salts / Q000378:metabolism*; D001692:Biological Transport; D002635:Chenodeoxycholic Acid / Q000378:metabolism; D002845:Chromatography / Q000379:methods; D003016:Clostridium perfringens / Q000201:enzymology*; D003067:Coenzymes / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000378:metabolism*; D008095:Lithocholic Acid / Q000378:metabolism; D019998:Racemases and Epimerases / Q000378:metabolism
D001647:Bile Acids and Salts; D003067:Coenzymes; D002635:Chenodeoxycholic Acid; D008095:Lithocholic Acid; D006859:Hydrogen; D019998:Racemases and Epimerases