Cytochrome P450-dependent change in UDP-glucuronosyltransferase function and its reverse regulation

Cytochrome P450 (P450, CYP) and UDP-glucuronosyltransferase (UGT) are important enzymes involved in phase I and II drug metabolism, respectively. It has long been believed that these enzymes work separately, because their topology with regard to the endoplasmic reticulum membrane is very different and the location of the two enzymes is separated by the membrane. However, cumulative evidence suggests that these enzymes interact with each other to modify their respective functions. This review mainly focuses on a P450-dependent alteration in UGT function and discusses the relevance of this modification to the polymorphic nature of drug metabolism mediated by UGTs. Also, we describe the selectivity of P450/UGT isoforms in terms of their pairing and possible P450/UGT domains serving the interactions. The reverse modulation, that is, the alteration of P450 function by UGT, is also described.