Hyodeoxycholate-6-O-glucuronide cannot be quantitated with 3 alpha-hydroxysteroid dehydrogenase.
The reaction of the 6-hydroxylated bile acid, hyodeoxycholic acid, and its 6-O-glucuronide conjugate with 3 alpha-hydroxysteroid dehydrogenase was examined. A standard end-point assay and determination of the initial rates of reaction showed only minimal activity of the enzyme toward hyodeoxycholate-6-glucuronide in spite of the presence of a free 3 alpha-hydroxyl group. It was established that 6-hydroxylation itself did not significantly affect the enzyme reaction. It is concluded that the 6-glucuronide either blocks or hinders enzyme access to the 3-hydroxyl group.
D015096:3-Hydroxysteroid Dehydrogenases; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific); D003840:Deoxycholic Acid / Q000031:analogs & derivatives* / Q000032:analysis*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy
D003840:Deoxycholic Acid; C054624:hyodeoxycholate-6-O-glucuronide; C010471:hyodeoxycholic acid; D015096:3-Hydroxysteroid Dehydrogenases; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific)