Solubilization and separation of delta5,3beta-hydroxysteroid dehydrogenase and 3-oxosteroid-delta4-delta5-isomerase from bovine adrenal cortex microsomes.

A physical separation of delta5,3beta-hydroxysteroid dehydrogenase and 3-oxosteroid delta4-delta5-isomerase solubilized from bovine adrenocortical microsomes is described for the first time. The solubilization as well as the separation was carried out with a mixture of a detergent: a substituted betaine (Empigen BB/P) and sodium cholate. This latter detergent protects isomerase from complete inactivation by Empigen and is necessary for the recovery of a significant amount of soluble isomerase. Separation of dehydrogenase and isomerase was successfully accomplished by the use of a DEAE-Biogel A anion-exchanger. Dehydrogenase activity was eluted, while the isomerase was retained. Measurements of dehydrogenase activity with androst-5-en-3beta-ol-17-one, pregnen-3beta-ol-20-one and pregn-5-en-(3beta,17alpha)-diol-20-one and of isomerase activity with androst-5-en-(3,17)-dione and pregn-5-en-(3,20)-dione suggested that more than one isomerase and more than one dehydrogenase form were present.