20alpha-hydroxysteroid dehydrogenase

In enzymology, a 20alpha-hydroxysteroid dehydrogenase is an enzyme that catalyzes the chemical reaction


 * 17alpha,20alpha-dihydroxypregn-4-en-3-one + NAD(P)+ $$\rightleftharpoons$$ 17alpha-hydroxyprogesterone + NAD(P)H + H+

The 3 substrates of this enzyme are 17alpha,20alpha-dihydroxypregn-4-en-3-one, NAD+, and NADP+, whereas its 4 products are 17alpha-hydroxyprogesterone, NADH, NADPH, and H+.

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 20alpha-hydroxysteroid:NAD(P)+ 20-oxidoreductase. Other names in common use include 20alpha-hydroxy steroid dehydrogenase, 20alpha-hydroxy steroid dehydrogenase, 20alpha-HSD, and 20alpha-HSDH. This enzyme participates in c21-steroid hormone metabolism.

Structural studies
As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes, , and.