Oxidative activation and inactivation of the carcinogen 2-acetylaminofluorene by various purified cytochromes P-450 from 3-methylcholanthrene pretreated rats.

Ring- and N-hydroxylations of 2-acetylaminofluorene (AAF) have been examined in a reconstituted system with 4 purified hepatic microsomal cytochromes P-450 isolated from 3-methylcholanthrene (MC)-pretreated rats. Among these 4 isozymes, P-450D showed the most activity whereas P-450C was devoid of any activity; two other P-450s exhibited moderate activity. These and Ouchterlony's double diffusion analyses suggest involvement of multiple cytochromes P-450 in AAF oxidations.