Twenty years of biochemistry of human P450s: purification, expression, mechanism, and relevance to drugs.

Today cytochrome P450 (P450) research is accepted as an integral part of drug development and discovery. Work leading to this point included biochemical studies on P450 in experimental animal models and application to human systems. The development of recombinant expression systems has been an important part of the progress, and in this article we describe some recently developed bacterial systems that can be used for the production of metabolites, genotoxicity testing, and screening in random mutagenesis work. Rate-limiting aspects of P450 reactions vary with particular systems, and further investigations are in order. Non-ionic detergents have been utilized widely in P450 purification work; these compounds are now shown to be substrates for P450s. These oxidations are not only of fundamental interest in expanding the repertoire of P450 substrates but have significance in light of human exposure to these compounds.