12alpha-hydroxysteroid dehydrogenase
In enzymology, 12alpha-hydroxysteroid dehydrogenase is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are the bile acid, cholic acid, and oxidised nicotinamide adenine dinucleotide phosphate. Its products are 12-ketochenodeoxycholic acid, reduced NADPH, and a proton.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 12alpha-hydroxysteroid:NADP+ 12-oxidoreductase. Other names in common use include 12alpha-hydroxy steroid dehydrogenase, 12alpha-hydroxy steroid dehydrogenase, NAD+-dependent 12alpha-hydroxysteroid dehydrogenase, and NADP+-12alpha-hydroxysteroid dehydrogenase. This enzyme is involved in a metabolic pathway that degrades bile acids into cholesterol.