Modelling human cytochromes P450 for evaluating drug metabolism: an update

Cytochrome P450 (CYP) enzymes represent the major catalysts for the Phase 1 metabolism of drugs and other xenobiotics in Mammalia, including Homo sapiens. There is considerable current interest in evaluating and, consequently, predicting the metabolic fate of new chemical entities (NCEs) via modelling molecular interactions with P450 constructs, such that sites of metabolism, particular CYP involvement and binding affinities, can be estimated. This paper focuses on the principles for homology modelling of typical enzyme-substrate interactions within the putative active sites of major P450s associated with drug metabolism in man. It also represents an update on previously published work in this journal /1/.