Oxidation of corticosteroids to steroidal carboxylic acids by an enzyme preparation from hamster liver

Abstract

Enzyme activity which catayzed oxidation of 11-deoxycorticosterone to 21-oic acid accompanied the detritiating enzyme (isomerase) of hamster liver. The metabolites isolated were 20.alpha.- and 20.beta.-hydroxy-3-oxo-pregn-4-en-21-oic acid and 3,20-dioxo-pregn-4-en-21-oic acid. When 21-hydroxy[4-14C,21-3H]pregn-4-en-3,20-dione was the substrate, about half of the 3H was retained in position 20 of the hydroxy acids. The system which catalyze conversion of the ketol side chain of corticosteroids to acid metabolities appeared to be a cluster of closely related enzymes. The hamster liver enzyme preparation provides a useful model system for studies on biosynthesis of acid metabolites of corticosteroids in man.