The 21-Hydroxysteroid Dehydrogenases of Liver

Studies on 21-3H-labeled corticosteroids: evidence for isomerization of the ketol side chain of 11-deoxycorticosterone by a hamster liver enzyme

“…A reversible oxidation of DOC to 21-dehydroDOC provides a possible explanation for the exchange reaction. The known 21-hydroxysteroid dehydrogenases (Monder and White, 1965) utilize NAD or NADR as a cosubstrate. We found that 21-hydroxysteroid dehydrogenase did not catalyze the net loss of tritium from the [4-l4C, 21-3H]-labeled DOC at pH 8.5 to 9.5 over a 90-min incubation period with NAD+.…”