Sodium periodate, sodium chlorite, organic hydroperoxides, and H 2O 2 as hydroxylating agents in steroid hydroxylation reactions catalyzed by partially purified cytochrome P-450

Abstract

Summary The mechanism of androstenedione hydroxylation has been examined by employing NADPH, NaIO4, NaCLO2, H2O2, and organic hydroperoxides as hydroxylating agents and partially purified cytochrome P-450, prepared from phenobarbital-induced rat liver microsomes, as the catalyst. The NADPH-supported hydroxylation also required NADPH-cytochrome P-450 reductase. Androstenedione was hydroxylated in the 6β-, 7α-, and 16α-positions to varying degrees depending on the hydroxylating agent. NaIO4 was the most effective agent followed by cumene hydroperoxide, NADPH, Linoleic acid hydroperoxide, NaCLO2, t -butyl hydroperoxide, and H2O2. It was suggested that the ferryl ion (compound I) of cytochrome P-450 is the common “activated oxygen” species in these hydroxylations.