STUDY OF SPECIFICITY OF ACTION OF OXIDOREDUCTASE CHOLESTEROL OXYGEN ON CERTAIN STEROLS AND RELATED SUBSTANCES

Abstract

The action of oxygen cholesterol oxidoreductase (EC 1.1.3.6) extracted from Nocardia erythropolis on different sterols was studied. The disappearance of the substrate by chromatography on thin layers of silicic acid, the formation of H2O2 by Roschlau''s reaction and changes in the absorption spectrum between 220 and 320 nm were noted simultaneously. Sterol oxidase presents a broad spectrum of activity. It catalyzes the transformation into ketone of the secondary alcohol group at the 3 .beta. position of sterols which possess in the C17 position a lateral chain of at least 2 C atoms. The reaction does not proceed if there exists in the C5 position an H in the cis position or if 2 H atoms linked to C 4 are substituted. Only oxidation products derived from sterols, possessing a double bond situated in the 4-5 or 5-6 position, present an absorption band between 240 and 250 nm.