Monoclonal antibodies against human liver cytochrome P-450

Monoclonal hybridomas which produce antibodies against human liver microsomal cytochrome P-450 were developed. Three similar hybridomas produced antibodies which recognized an epitope specific to a family of human P-450 isozymes (P-450(5)). This epitope was also present on cytochrome P-450 PCN-E (pregnenolone-16 alpha-carbonitrile induced) from rat liver microsomes, but this isozyme differed from the human P-450(5) by its molecular weight. These antibodies enabled us to quantify cytochrome P-450(5) in human liver microsomes and to demonstrate an important quantitative polymorphism in the human liver monooxygenase system.