Major advances have been made in recent years in clarifying the molecular properties of the cytochrome P-450 system. These advances stem, in practical terms, from the generally recognized importance of cytochrome P-450 in the metabolism of drugs and in the bioactivation of xenobiotics to toxic products. The fascinating multiplicity and differential regulation of cytochrome P-450 isozymes, and their ability to catalyze extraordinarily difficult chemical transformations, have independently drawn many chemists and biochemists into the P-450 circle. Progress in the field, from a technical point of view, has been propelled by the de velopment of reliable procedures for the purification of membrane-bound enzymes, by the growing repertoire of molecular biological techniques, and by the development of chemical models that mimic the catalytic action of P-450. As a result, our understanding of the P-450 system is moving from the descriptive, pharmacological level into the tangible realm of atomic detail. The rapid progress and multidisciplinary character of the cytochrome P-450 field, which cuts across the lines that traditionally divide disciplines as diverse as inorganic chemistry and genetics, have created a need for an up-to-date evaluation of the advances that have been made. It is hoped that this book, with its molecular focus on the cytochrome P-450 system, will alleviate this need. The authors of the individual chapters have strived to emphasize recent results without sacrificing the background required to make their chapters comprehensible to informed nonspecialists.

Cytochrome P450: Structure, Mechanism, and Biochemistry, third edition is a revision of a review that summarizes the current state of research in the field of drug metabolism. The emphasis is on structure, mechanism, biochemistry, and regulation. Coverage is interdisciplinary, ranging from bioinorganic chemistry of cytochrome P450 to its relevance in human medicine. Each chapter provides an in-depth review of a given topic, but concentrates on advances of the last 10 years.

During half a century, cytochrome P450 in its original uniqueness as an optically "wrong" cytochrome has attracted many investigators, who have contributed to the unveiling of a bewildering multiplicity of biologically important functions of the, by now very large, superfamily of cytochrome P 450 enzymes. With its discovery in 1958 and with the advent of more refined spectroscopic methodologies, through the double wavelength spectrophotometry, the mysterious enzyme system began to reveal its secrets in a swift stream of investigative successes. As one of the most extensively studied enzyme systems worldwide the interest in cytochromes P450 very much reflects its importance in the elimination of drugs and other chemicals from the body and its role in chemical toxicity and in the aetiology of diseases such as cancer. There has been significant progress in research in this area in recent years and current books on this subject are now out of date. This much needed, new, fully up-to-date publication fills this gap and emphasises the new relevant topics that have emerged during the last decade in an easily accessible manner. The enzyme system, cytochromes P450, comprises a number of families/subfamilies, and the focus of the book is to deal with each individually, furnishing information directly relevant to scientists involved in the development of chemicals, in particular in the evaluation of their safety. The book has contributions from internationally respected scientists who are research-active in the relevant areas. The authors have made extensive use of figures and tables so that the reader can access the necessary information without always having to read the text. In addition, a very extensive, user-friendly index is a unique hallmark of the book. Part A of this monograph introduces the reader to the current knowledge of the evolutionary development of cytochrome P450 structure and function. Furthermore, it deals with the role of this enzyme in the formation of reactive intermediates. The shrewd and extensive utilisation of the molecular biology methodology very rapidly led to a vast body of enzymes calling for a classification of the plethora of different cytochromes P450 (the superfamily) into families and subfamilies. This is aptly exemplified by the ten chapters in Part B of this book, dealing with ten subfamilies and two families of cytochrome P450. Part C offers an insight into another aspect of cytochrome P450 research, namely its regulation through receptor-mediated stimuli - as opposed to enzyme induction or inhibition. The final chapter translates the current data on one of several drug metabolising systems into clinical application and highlights the role of cytochromes P450 in the treatment of neoplastic growth. The book deals extensively with each family/subfamily of the cytochromes P450 that contribute to the metabolism of xenobiotics. Essential and invaluable information is provided for the industrial research scientist working with fine chemicals, and especially those in the pharmaceutical industry, dealing with the safety evaluation of chemicals or being involved in the study of their metabolism, pharmacokinetics and toxicological properties. It should also prove of interest to Regulators concerned with the safety evaluation of chemicals, research pharmacologists and toxicologists, and postgraduate students studying drug metabolism and toxicology at an advanced level.

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.

The most complete and up-to-date survey of this important superfamily of enzymes, including the first ever coverage of the forms involved in steroid hormone biosynthesis. The components of the enzyme system, the reaction mechanisms involved, and the evolution and nomenclature are analyzed, as is the hepatic microsomal enzyme in a large number of species, illustrating the very wide implications for life processes.

This book describes in 13 chapters mechanisms of P450 used to monooxygenate substrates via the NAD(P)H/O2 pathway using its peroxidase and peroxygenase functions. P450 also utilizes peroxides, peracids, periodate and iodosobenzene to oxygenate substrates via the shunt pathway. Also described are mechanisms used in the oxidation of pharmaceuticals by CYP3A4; acyl- carbon cleavage by CYP17A1, CYP19A1 and CYP51A1; metabolism of tetrabromodiphenyl ethers and bile acids by CYP2B6 and CYP3A4; metabolism of ω-6 and ω-3 polyunsaturated fatty acids; H2O2-mediated peroxygenation of substrates using substrate misrecognition; P450 oxidative reactions using electrochemical methods; electron transfer to P450 by redox proteins; hydroxylation of 1,8-cineole by P450cin; and peroxygenation by unspecific peroxygenases using H2O2. The topics covered are relevant to P450 researchers, professors and students from a variety of disciplines ranging from pharmacology, toxicology and microbiology to chemistry.

A practice-oriented desktop reference for medical professionals, toxicologists and pharmaceutical researchers, this handbook provides systematic coverage of the metabolic pathways of all major classes of xenobiotics in the human body. The first part comprehensively reviews the main enzyme systems involved in biotransformation and how they are orchestrated in the body, while parts two to four cover the three main classes of xenobiotics: drugs, natural products, environmental pollutants. The part on drugs includes more than 300 substances from five major therapeutic groups (central nervous system, cardiovascular system, cancer, infection, and pain) as well as most drugs of abuse including nicotine, alcohol and "designer" drugs. Selected, well-documented case studies from the most important xenobiotics classes illustrate general principles of metabolism, making this equally useful for teaching courses on pharmacology, drug metabolism or molecular toxicology. Of particular interest, and unique to this volume is the inclusion of a wide range of additional xenobiotic compounds, including food supplements, herbal preparations, and agrochemicals.