Inhibition of 2-acetylaminofluorene oxidations by monoclonal antibodies specific to 3-methylcholanthrene-induced rat liver cytochrome P450.

The inhibitory effects of ten monoclonal antibodies specific for methylcholanthrene (MC)-induced P450 were determined on both C- and N-hydroxylations of 2-acetylaminofluorene (AAF) by liver microsomes from rats pretreated with MC, phenobarbital as well as untreated animals. The inhibitory effects of these antibodies were also determined on AAF hydroxylations by purified rat liver MC-P450. The inhibition patterns of AAF hydroxylations with both microsomes and the purified P450 indicate that the formation of 7-OH-, 5-OH-, 3-OH-, 1-OH- and N-OH-AAF was catalyzed by the same unique isoenzyme or at least isoenzymes of common antigenic determinants.