Regulation, function, and tissue-specific expression of cytochrome P450CYP1B1

Cytochrome P450 CYP1B1 is a relatively recently identified member of the CY P1 gene family. The purpose of this commentary is to review the regulatory mechanisms, metabolic specificity, and tissue-specific expression of this c ytochrome P450 and to highlight its unique properties. The regulation of CY P1B1 involves a variety of both transcriptional and post-transcriptional me chanisms. CYP1B1 can metabolize a range of toxic and carcinogenic chemicals in vitro but in some cases with a unique stereoselectivity. Estradiol 4-hy droxylation appears to be a characteristic reaction catalyzed by human CYP1 B1. However, there are considerable species differences regarding the regul ation, metabolic specificity. and tissue-specific expression of this P450, In humans CYP1B1 is overexpressed in tumor cells, and this has important im plications for tumor development and progression and the development of ant icancer drugs specifically activated by CYP1B1.