Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. In the epoxidation of arachidonic acid it generates only 14,15- and 11,12-cis-epoxyeicosatrienoic acids. It is the principal enzyme responsible for the metabolism the anti-cancer drug paclitaxel (taxol).Romkes M., Biochemistry 30:3247-3255(1991).Ged C., Biochim. Biophys. Acta 1088:433-435(1991).Zeldin D.C., Arch. Biochem. Biophys. 322:76-86(1995).