Partial purification of cytochrome P450 from rat brain and demonstration of estradiol hydroxylation

Cytochrome P450 was partially purified from brain microsomes of untreated rats. A difference spectrum of the dithionite-reduced CO-complex of the purified P450 showed essentially the hemeprotein absorbing exclusively at 449 nm. The purified brain P450 was able to catalyze estradiol (E2) hydroxylation leading to the formation of 6 alpha- and 6 beta-hydroxy(OH)E2, 4-OHE2, estrone, 6-oxoE2, 2-OHE2, 15 alpha-OHE2 and estriol. These results demonstrate that rat brain P450 is active in estradiol hydroxylation.