Lipoxygenases and Their Products


Book Description

Lipoxygenases and Their Products provides a cogent summary of the advances in understanding lipoxygenases and their products, emphasizing their pharmacology and pathophysiology; regulation and structure; physiological role; and receptors and receptor antagonists. This text also reviews the literature where specific receptor antagonists (as opposed to enzymatic inhibitors) have been used to characterize the pharmacologic action and the pathophysiologic roles of some of lipoxygenase products of arachidonic acid metabolism. This book is organized into 11 chapters and begins with an overview of the biochemical, pharmacological, and pathophysiological aspects of 5-lipoxygenase products of arachidonic acid metabolism in the respiratory, cardiovascular, renal, gastrointestinal, and central nervous systems. The discussion then shifts to human 5-lipoxygenase, emphasizing this enzyme purification, stimulatory factors, and membrane translocation. The reader is methodically introduced to 5-lipoxygenase activity in rats and pigs; the potential and therapeutic value of 5-lipoxygenase inhibitors; the distribution of 15-lipoxygenase in cells or tissues; and products formed through the 15-lipoxygenase pathway. This book also considers lipoxins and third-generation peptidoleukotriene receptor antagonists, and then concludes with a summary of the physiological and pathophysiological effects of leukotrienes and lipoxins in a variety of organs. This book is of interest to scientists interested in arachidonic acid and its metabolites, to scientists engaged in drug discovery-and-development activities in academia and the pharmaceutical industry, and to clinicians interested in diseases associated with leukotrienes and related products.




Lipoxygenases and their Metabolites


Book Description

This book is a result of the First Conference on Lipoxygenases, held at Malta, May 17th-2l st, 1997. The goal was very ambitious: having lipoxygenases as a focus for distant and diverse experimental approaches, we brought together scientists to discuss and build a consensus on the biological role of lipoxygenases. Although still fuzzy in many details, the Malta conference has shown that a unifying view on lipoxygenases is finally taking shape, and that the experimental evidence of links and conjugations among events OCCUf ing from cell membranes to intracellular compartments and the nucleus is becoming in creasingly convincing. The editors are deeply grateful to Hospital for Sick Children, Toronto, Free Univer sity Berlin, NOAA Sea Grant College Program (U. S. A. ), Schering, Berlin (F. R. G. ), and Cayman Chemicals, Ann Arbor, Michigan (U. S. A. ), for their generous financial support, which was crucial in making the conference a scientific success. The conference received financial support from a number of additional sponsors, and we express our gratitude to Abbott Labs (U. S. A. ), Air Malta (Malta), Ass. Int. Cancer Res. (U. K. ), Biometra (F. R. G. ), Bayer AG (F. R. G. ), IBL Co. (F. R. G. ), Merck Frosst (Canada), Perkin Elmer (F. R. G. ), Scotia Pharmaceuticals (Canada), Searle (U. S. A. ), SPI Chemicals (France), and TOPCRO (Austria).




Lipid Oxidation


Book Description

In this second edition, Edwin Frankel has updated and extended his now well-known book Lipid oxidation which has come to be regarded as the standard work on the subject since the publication of the first edition seven years previously. His main objective is to develop the background necessary for a better understanding of what factors should be considered, and what methods and lipid systems should be employed, to achieve suitable evaluation and control of lipid oxidation in complex foods and biological systems. The oxidation of unsaturated fatty acids is one of the most fundamental reactions in lipid chemistry. When unsaturated lipids are exposed to air, the complex, volatile oxidation compounds that are formed cause rancidity. This decreases the quality of foods that contain natural lipid components as well as foods in which oils are used as ingredients. Furthermore, products of lipid oxidation have been implicated in many vital biological reactions, and evidence has accumulated to show that free radicals and reactive oxygen species participate in tissue injuries and in degenerative disease. Although there have been many significant advances in this challenging field, many important problems remain unsolved. This second edition of Lipid oxidation follows the example of the first edition in offering a summary of the many unsolved problems that need further research. The need to understand lipid oxidation is greater than ever with the increased interest in long-chain polyunsaturated fatty acids, the reformulation of oils to avoid hydrogenation and trans fatty acids, and the enormous attention given to natural phenolic antioxidants, including flavonoids and other phytochemicals.




Seed Proteins


Book Description

Seeds provide more than half of the world's intake of dietary protein and energy and thus are of immense economic, cultural and nutritional importance. Proteins can account for up to 40% of the dry weight of various types of seeds, thereby making a large contribution to the nutritional quality and processing properties of seeds. It is, therefore, not surprising that seed proteins were among the first plant components to be systematically studied, some 250 years ago, and have been a major focus of research over the past 100 years. The properties and behaviour of seed proteins pervade modem life in numerous ways. For example, legume and cereal proteins are used'in the production of a wide range of meat-free foods; the process of bread-making is dep~ndent on the physical chemical properties of wheat seed proteins; and in developed, as well as developing, countries, nutritional deficiencies among vegetarian diets are avoided through balancing legume and cereal seeds as sources of dietary proteins. Understanding seed proteins, in order to improve their composition and properties and to increase their concentrations, will thus continue to be an important research objective for the future. The present volume represents the culmination of a long-discussed plan of the editors, to bring together the best international authorities in order to compile a definitive monograph on biological, biochemical, molecular and genetic aspects of seed proteins.




12-lipoxygenases


Book Description

The lipoxygenase enzymes are non-heme, non-sulfur iron dioxygenases that are widely distributed throughout plants, animals, fungi and some bacteria. This family of enzymes plays a major role in polyunsaturated fatty acid metabolism because they catalyze the incorporation of molecular oxygen into fatty acids containing a 1,4-pentadiene moiety producing hydroperoxide products. In mammals, the products of the dioxygenation catalyzed by lipoxygenases, hydroperoxyeicosatetraenoic acid (HPETEs), are intermediates in the formation of bioregulators including leukotrienes, hepoxilins and HETEs, that are implicated in a variety of human conditions such as inflammation, fever, arthritis and cancer. 12-Lipoxygenases are mammalian lipoxygenases that catalyze the conversion of arachidonic acid into 12-hydroperoxy-5,8,10,14-eicosatetraenoic acid (12-HPETE). Actually, 12-HPETE is a precursor to the formation of the hydroxy fatty acid 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) and also epoxy fatty acids called hepoxylins. There are three isoforms of 12-lipoxygenase named after the cells where they are found: leukocyte, platelet and epidermis type-enzymes. Even if the leukocyte and the platelet 12-lipoxygenase catalyze the same reaction, they differ by their tissue distribution, their substrate specificity, their primary structure and size. They are also involved in different kinds of diseases as inflammation, hypertension and diabetes. The goal of this research was to investigate the human platelet and porcine leukocyte 12-lipoxygenases. In order to study both 12-lipoxygenases, they need to be expressed, purified and in the best case crystallized to get the 3D structure. This thesis presents the expression and purification protocols that lead to the preparation of large amounts of pure porcine leukocyte 12-lipoxygenase. Several biophysical analyses were performed to characterize the protein in solution such as dynamic light scattering (DLS), differential scanning calorimetry (DSC), EPR spectroscopy and mass spectrometry. Many crystallization experiments were also tried in order to obtain diffraction-quality crystals of porcine leukocyte 12-lipoxygenase. As for the human platelet 12-lipoxygenase, the expression step turned out to be less successful, and leads to low yields and unsatisfactory purity.




Autoxidation in Food and Biological Systems


Book Description

The material presented in this book deals with basic mechanisms of free radical reactions in autoxidation processes and anitoxidant suppression of autoxidation of foods, biochemical models and biologi cal systems. Autoxidation in foods and corresponding biological effects are usually approached separately although recent mechanistic developments in the biochemistry and free radical chemistry of per oxides and their precursors tend to bring these two fields closer. Apparent ability of antioxidants in diets to reduce the inci dence of cancer has resulted in scrutiny of autoxidized products and their precursors as possibly toxic, mutagenic and carcinogenic agents. Mechanisms of any of these effects have been barely ad dressed. Yet we know now that free radicals, as esoteric as they were only a few decades ago, are being discovered in foods, biochem ical and biological systems and do play a role in the above-mentioned causalities. The purpose of the Workshop and the resulting book was to give a unifying approach towards study of beneficial and deleterious effects of autoxidation, based on rigorous scientific considerations. It is our hope that the material presented in this book will not only provide a review of the "state of the art" of autoxidation and anti oxidants, but also reflect the interaction which occurred during the Workshop between workers using model sytems, and food and biological systems.




The Resolution of Inflammation


Book Description

This book provides readers with an up-to-date and comprehensive view on the resolution of inflammation and on new developments in this area, including pro-resolution mediators, apoptosis, macrophage clearance of apoptotic cells, possible novel drug developments.




Amphioxus Immunity


Book Description

Amphioxus Immunity: Tracing the Origin of Human Immunity covers a remarkable range of information about Amphioxus and its evolutionary context. This compilation of what is currently known about Amphioxus, with a sharp focus on its immune system, includes 13 topics, such as: Amphioxus as a model for understanding the evolution of vertebrates basic knowledge of immunology immune organs and cells of amphioxus a genomic and transcriptomic view of the Amphioxus immunity pattern recognition system in Amphioxus transcription factors in Amphioxus the complement system of Amphioxus the oxidative burst system in Amphioxus immune effectors in Amphioxus lipid signaling of immune response in Amphioxus apoptosis in amphioxus; primitive adaptive immune system of Amphioxus and future research directions This valuable reference book is loaded with information that will be useful for anyone who wishes to learn more about the origin of vertebrates and adaptive immunity. Provides new evidence on the origin of the adaptive immune system, the evolution of innate immunity, and evolution-stage specific immune defense mechanisms Not only presents the cells and molecules involved in the adaptive immune response in Amphioxus, but also characterizes the origination and evolution of the gene families and pathways involved in innate immunity Includes much pioneering work, from the molecular, genomic, and cellular to the individual level