Incorporation of bovine adrenal 3 beta-hydroxy-5-ene steroid dehydrogenase/delta 5-delta 4 isomerase into phospholipid vesicles.

3 beta-Hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD/I) and cytochrome P-450C21 were co-purified from bovine adrenocortical microsomes by an improved method. The 3 beta-HSD/I was successfully incorporated into liposomal membranes in which the enzyme activity was greatly stabilized. Enzymatic activities and kinetic parameters of the 3 beta-HSD/I proteoliposomes were almost the same as those of the solubilized form.