The Ubiquitous Roles of Cytochrome P450 Proteins


Book Description

Helmut Sigel, Astrid Sigel and Roland K.O. Sigel, in close cooperation with John Wiley & Sons launch a new Series “Metal Ions in Life Sciences”. There exists a whole range of books on Cytochromes P450, but none with the focus of this volume. This new volume in the Series concentrates on current hot topics in the area and tries to work out the underlying common developments. As a result the reader will find a systematic account of new results in this exciting research area. The table of contents gives an idea on the wide span of chapters, starting with overviews and the presentation of specific systems, and ending with chapters on carbon-carbon bond cleavage by P450 sytems, drug metabolism as catalyzed by P450 systems, decomposition of xenobiotics by P450 enzymes and design and engineering of new P450 systems.




Cytochromes P450


Book Description

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There has been significant progress in research in this area in recent years and current books on this subject are now out of date.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.




Monooxygenase, Peroxidase and Peroxygenase Properties and Mechanisms of Cytochrome P450


Book Description

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.




Cytochrome P450


Book Description

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.




Mitochondria and Anaerobic Energy Metabolism in Eukaryotes


Book Description

Mitochondria are sometimes called the powerhouses of eukaryotic cells, because mitochondria are the site of ATP synthesis in the cell. ATP is the universal energy currency, it provides the power that runs all other life processes. Humans need oxygen to survive because of ATP synthesis in mitochondria. The sugars from our diet are converted to carbon dioxide in mitochondria in a process that requires oxygen. Just like a fire needs oxygen to burn, our mitochondria need oxygen to make ATP. From textbooks and popular literature one can easily get the impression that all mitochondria require oxygen. But that is not the case. There are many groups of organismsm known that make ATP in mitochondria without the help of oxygen. They have preserved biochemical relicts from the early evolution of eukaryotic cells, which took place during times in Earth history when there was hardly any oxygen avaiable, certainly not enough to breathe. How the anaerobic forms of mitochondria work, in which organisms they occur, and how the eukaryotic anaerobes that possess them fit into the larger picture of rising atmospheric oxygen during Earth history are the topic of this book.




The Endothelium


Book Description

The endothelium, a monolayer of endothelial cells, constitutes the inner cellular lining of the blood vessels (arteries, veins and capillaries) and the lymphatic system, and therefore is in direct contact with the blood/lymph and the circulating cells. The endothelium is a major player in the control of blood fluidity, platelet aggregation and vascular tone, a major actor in the regulation of immunology, inflammation and angiogenesis, and an important metabolizing and an endocrine organ. Endothelial cells controls vascular tone, and thereby blood flow, by synthesizing and releasing relaxing and contracting factors such as nitric oxide, metabolites of arachidonic acid via the cyclooxygenases, lipoxygenases and cytochrome P450 pathways, various peptides (endothelin, urotensin, CNP, adrenomedullin, etc.), adenosine, purines, reactive oxygen species and so on. Additionally, endothelial ectoenzymes are required steps in the generation of vasoactive hormones such as angiotensin II. An endothelial dysfunction linked to an imbalance in the synthesis and/or the release of these various endothelial factors may explain the initiation of cardiovascular pathologies (from hypertension to atherosclerosis) or their development and perpetuation. Table of Contents: Introduction / Multiple Functions of the Endothelial Cells / Calcium Signaling in Vascular Cells and Cell-to-Cell Communications / Endothelium-Dependent Regulation of Vascular Tone / Conclusion / References




Transporters and Drug-Metabolizing Enzymes in Drug Toxicity


Book Description

TRANSPORTERS AND DRUG-METABOLIZING ENZYMES IN DRUG TOXICITY Explore up-to-date coverage on the interaction between drug metabolism enzymes, transporters, and drug toxicity with this leading resources Transporters and Drug-Metabolizing Enzymes in Drug Toxicity delivers a comprehensive and updated review of the relationship between drug metabolism, transporters, and toxicity, providing insights into a major challenge in drug development – accurate assessment of human drug toxicity. Combining two disciplines frequently considered independently of one another, the book combines drug metabolism and toxicology with a focus on the role of biotransformation on drug toxicity and as a major factor for species and individual differences. Mechanism and species differences in drug metabolizing enzymes and transporters are discussed, as are the methods used to investigate the role of drug metabolizing enzymes and transporters in drug toxicity. Finally, the distinguished authors describe promising new experimental approaches to accurately assessing human drug toxicity via the consideration of human-specific drug metabolism in toxicity assays. In addition to topics as diverse as extended clearance models, experimental approaches for the estimation of DILI potential of drug candidates and roles of transporters in renal drug toxicity, readers will also enjoy the inclusion of such subjects as: A thorough overview of and introduction to drug metabolism and transporters and drug toxicity An exploration of drug metabolism enzymes and transporter activities as risk factors of marketed drugs associated with drug-induced fatalities A discussion of human-based in vitro experimental models for the evaluation of metabolism-dependent drug toxicity A treatment of mechanism-based experimental models for the evaluation of BSEP inhibition and DILI An examination of transporters and cochlea toxicity Perfect for scientists, students, and practitioners with interests in metabolism, toxicology, and drug development in the pharmaceutical industry, Transporters and Drug-Metabolizing Enzymes in Drug Toxicity will also earn a place in the libraries of medicinal chemists, pharmacologists, biochemists, toxicologists, and regulators in the pharmaceutical and health industries.




Advances in Computational Toxicology


Book Description

This book provides a comprehensive review of both traditional and cutting-edge methodologies that are currently used in computational toxicology and specifically features its application in regulatory decision making. The authors from various government agencies such as FDA, NCATS and NIEHS industry, and academic institutes share their real-world experience and discuss most current practices in computational toxicology and potential applications in regulatory science. Among the topics covered are molecular modeling and molecular dynamics simulations, machine learning methods for toxicity analysis, network-based approaches for the assessment of drug toxicity and toxicogenomic analyses. Offering a valuable reference guide to computational toxicology and potential applications in regulatory science, this book will appeal to chemists, toxicologists, drug discovery and development researchers as well as to regulatory scientists, government reviewers and graduate students interested in this field.




Handbook of Pharmacogenomics and Stratified Medicine


Book Description

Handbook of Pharmacogenomics and Stratified Medicine is a comprehensive resource to understand this rapidly advancing field aiming to deliver the right drug at the right dose to the right patient at the right time. It is designed to provide a detailed, but accessible review of the entire field from basic principles to applications in various diseases. The chapters are written by international experts to allow readers from a wide variety of backgrounds, clinical and non-clinical (basic geneticists, pharmacologists, clinicians, trialists, industry personnel, ethicists) to understand the principles underpinning the progress in this area, the successes, failures and the challenges ahead. To be accessible to the widest range of readers, the clinical application section introduces the disease process, existing therapies, followed by pharmacogenomics and stratified medicine details.Medicine is the cornerstone of modern therapeutics prescribed on the basis that its benefit should outweigh its risk. It is well known that people respond differently to medications and in many cases the risk-benefit ratio for a particular drug may be a gray area. The last decade has seen a revolution in genomics both in terms of technological innovation and discovering genetic markers associated with disease. In parallel there has been steady progress in trying to make medicines safer and tailored to the individual. This has occurred across the whole spectrum of medicine, some more than others. In addition there is burgeoning interest from the pharmaceutical industry to leverage pharmacogenomics for more effective and efficient clinical drug development. - Provides clinical and non-clinical researchers with practical information normally beyond their usual areas of research or expertise - Includes an basic principles section explaining concepts of basic genetics, genetic epidemiology, bioinformatics, pharmacokinetics and pharmacodynamics - Covers newer technologies– next generation sequencing, proteomics, metabolomics - Provides information on animal models, lymphoblastoid cell lines, stem cells - Provides detailed chapters on a wide range of disease conditions, implementation and regulatory issues - Includes chapters on the global implications of pharmacogenomics




Cadmium: From Toxicity to Essentiality


Book Description

Volume 11 provides in an authoritative and timely manner in 16 stimulating chapters, written by 40 internationally recognized experts from 11 nations, and supported by more than 2600 references, 35 tables, and over 100 illustrations, many in color, a most up-to-date view on the role of cadmium for life, presently a vibrant research area. MILS-11 covers the bioinorganic chemistry of Cd(II), its biogeochemistry, anthropogenic release into the environment, and speciation in the atmosphere, waters, soils, and sediments. The analytical tools for Cd determination, its imaging in cells, and the use of 113Cd NMR to probe Zn(II) and Ca(II) proteins are summarized, as are Cd(II) interactions with nucleotides, nucleic acids, amino acids, and proteins including metallothioneins. The phytoremediation by Cd(II)-accumulating plants, etc., the toxicology of Cd(II), its damage to mammalian organs, and its role as a carcinogen for humans, are highlighted.