PHYSICOCHEMICAL PROPERTIES OF REDUCED NICOTINAMIDE ADENINE-DINUCLEOTIDE PHOSPHATE-CYTOCHROME-P-450 REDUCTASE FROM BOVINE ADRENOCORTICAL MICROSOMES

Adrenocortical NADPH-cytochrome P-450 reductase (EC. 1.6.2.4) was purified from bovine adrenocortical microsomes by detergent solubilization and affinity chromatography. The purified cytochrome P-450 reductase was a single protein band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, being electrophoretically homogeneous and pure. The cytochrome P-450 reductase was optically a typical flavoprotein. The absorption peaks were at 274, 380 and 455 nm with shoulders at 290, 360 and 480 nm. The NADPH-cytochrome P-450 reductase was capable of reconstituting the 21-hydroxylase activity of 17α-hydroxyprogesterone in the presence of cytochrome P-45021 of adrenocortical microsomes. The specific activity of the 21-hydroxylase of 17α-hydroxyprogesterone in the reconstituted system using the excess concentration of the cytochrome P-450 reductase, was 15.8 nmol/min. © 1979.