Preparative-Scale Regio- and Stereospecific Oxidoreduction of Cholic Acid and Dehydrocholic Acid Catalyzed by Hydroxysteroid Dehydrogenases

Article abstract of DOI:10.1021/jo00365a009

NAD(P)-dependent hydroxysteroid dehydrogenases were used as catalysts for the oxidoreduction of the hydroxyl-keto groups of cholic acid (3α,7α,12α-trihydroxy-5β-cholan-24-oic acid) and dehydrocholic acid (3,7,12-trioxo-5β-cholan-24-oic acid).Cholic acid was regiospecifically oxidized, on a preparative scale, at each of the three possible positions, and dehydrocholic acid regio- and stereospecifically reduced at each of the three positions.The compounds were quantitatively transformed and the products were 97-99percent pure.The assignment of product structure was made by NMR.The nicotinamide cofactors were enzymatically regenerated, in situ, with the α-ketoglutarate/glutamate dehydrogenase, formate/formate dehydrogenase or glucose/glucose dehydrogenase systems.The enzymes were employed in the free form or immobilized on Sepharose CL-4B.