Cytochromes P450 (CYPs) comprise a large superfamily of proteins that are of central importance in the detoxification or activation of a tremendous number of natural and synthetic hydrophobic xenobiotics, including many therapeutic drugs, chemical carcinogens and environmental pollutants. CYPs are important in mediating interactions between an organism and its chemical environment and in the regulation of physiological processes. Cytochrome P450 Protocols, Third Edition focuses on high-throughput methods for the simultaneous analysis of multiple CYPs, substrates or ligands. Although the emphasis is on CYPs of mammalian origin, it reflects an increasing interest in CYPs of bacterial species. Also included are chapters on cytochrome P450 reductase (the redox partner of CYPs) and the flavin-containing monooxygenases (FMOs), and metabolomic and lipidomic approaches for identification of endogenous substrates of CYPs (‘de-orphanizing’ CYP substrates). Written in the successful Methods in Molecular BiologyTM series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible protocols, and notes on troubleshooting and avoiding known pitfalls. Authoritative and easily accessible, Cytochrome P450 Protocols, Third Edition provides a wide range of techniques accessible to researchers in fields as diverse as biochemistry, molecular biology, pharmacology, toxicology, environmental biology and genetics.