Download or read book Mechanistic Investigation Into Coenzyme B12 Enzymes written by Daniele Ciceri and published by . This book was released on 2000 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanistic Investigations Into Coenzyme B12 Dependent Enzymes written by Daniel James Darley and published by . This book was released on 1999 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coenzyme B12 Enzymes Part B written by and published by Academic Press. This book was released on 2022-05-27 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coenzyme B12 Enzymes, Part B, Volume 169 in the Methods in Enzymology series, highlights new advances in the field, with this new volume presenting interesting chapters on Structural characterization of cobalamin-dependent radical SAM methylases, Purification and characterization of sequential cobalamin-dependent radical SAM methylases ThnK and TokK in -lactam antibiotic biosynthesis, Characterization of the cobalamin-dependent radical S-adenosyl-L-methionine enzyme C-methyltransferase Fom3 in fosfomycin biosynthesis, Studies of OxsB and GenK, two B12-dependent radical SAM enzymes involved in natural product biosynthesis, Purification and structural elucidation of the cobalamin-dependent radical SAM enzyme OxsB, and more. Other chapters discuss Methods for studying the mechanisms of B12 enzymes, Computational investigations of B12 dependent enzymatic reactions, Using kinetic isotope effects to probe the mechanisms of adenosylcobalamin-dependent enzymes, Steady-state and pre-steady state kinetic analysis of ornithine 4,5-aminomutase, and more. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in Methods in Enzymology series Includes the latest information on B12 Enzymes
Download or read book Part I a Novel Vitamin B12 Catalyzed C C Bond Forming Reaction written by Christopher McGinley and published by . This book was released on 2005 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Modelling of Chemical Reactions Catalyzed by Cobalamin B12 dependent Enzymes written by Neeraj Kumar and published by . This book was released on 2013 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: The biologically active derivatives of vitamin B12 (cobalamin) possess the only examples containing organometallic Co-C bonds in living systems where the cleavage of Co-C bond initiates the catalytic cycle of the enzymatic reactions. In this dissertation, the electronic structure of various intermediates and the mechanistic details of the methyl transfer reactions involved in the catalytic cycle of the methionine synthase (MetH) have been computationally investigated using hybrid quantum mechanics/molecular mechanics (QM/MM) simulations, density functional theory (DFT), and complete active space self-consistent field with second order perturbation theory (CASSCF/QDPT2) computational methodologies. QM/MM calculations in particular reveal that the cob(I)alamin intermediate is not axially coordinated inside the enzyme which is consistent with free cob(I)alamin in solution, thus indicating an unprecedented role of enzyme-bound cob(I)alamin. In addition, DFT and high-level ab initio CASSCF/QDPT2 calculations further elucidate that the ground state of the cob(I)alamin is multiconfigurational where the diradical Co(II)-corrin· radical configuration contributes to the electronic structure of the cob(I)alamin intermediate, indicating a noninnocent behavior of the corrin ring. Furthermore, our QM/MM study reveals the traditionally assumed SN2 mechanism for the formation CH3-cob(III)alamin and the activation energy barrier for SN2 reaction is found to be comparable with respect to the experimental rate constant. However, the possibility of an alternative ET-based radical mechanism consistent with the close-lying diradical states has also been suggested, where an electron transfer (ET) from His-on cob(I)alamin to pterin ring of the protonated CH3-H4Folate takes place, indicating CoII(d7)-pterin radical (II*)I state, followed by a methyl radical transfer. The similar mechanistic details of SN2 and ET-based radical pathway have also been investigated in the second-half catalytic cycle of MetH as indicated by ionic and diradical states of the MeCbl:Homocysteine reaction complex. The mechanistic details of the MetH could also help in understanding some of the critical aspects related to the enzymatic methyl transfer reactions in other methyltransferases. In addition, the role of tyrosine active site in AdoCbl-dependent enzyme methylmalonyl CoA mutase (MCM) has been studied using density functional reactivity theory in which the charge separation propensity of electron transfer site is often distant from the proton-acceptor site, indicating that one electron reduced form AdoCb may be involved in the initial step of AdoCbl-dependent catalysis. As a result, the QM/MM optimized intermediates and transition states along with their calculated energetic profiles indicate that the reaction consisting of Co-C bond cleavage and subsequent hydrogen abstraction occurs in a concerted fashion when the reduced form of AdoCbl cofactor is involved in the reaction, whereas it takes place in a stepwise manner in a neutral form. The concerted pathway was further supported by the free energy metadynamics simulations.
Download or read book Radical SAM Enzymes written by and published by Academic Press. This book was released on 2018-08-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radical SAM Enzymes, Volume 606, the latest release in the Methods in Enzymology series, highlights new advances in the field, with this new volume presenting interesting chapters on the Characterization of the glycyl radical enzyme choline trimethylamine-lyase and its radical S-adenosylmethionine activating enzyme, Diphathimide biosynthesis, Radical SAM glycyl radical activating enzymes, Radical SAM enzyme BioB in the biosynthesis of biotin, Biogenesis of the PQQ cofactor, Role of MoaAC in the biogenesis of the molybdenum cofactor, Biosynthesis of the nitrogenase cofactor, Bioinformatics of the radical SAM superfamily, The involvement of SAM radical enzymes in the biosynthesis of methanogenic coenzymes, methanopterin and coenzyme F420, and more.
Download or read book Vitamin B 12 and B 12 Proteins written by Bernhard Kräutler and published by Wiley-VCH. This book was released on 1998-03-09 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text reviews the important developments in the "B12-field" with regard to biological, chemical, pharmaceutical and medicinal aspects. Topics of particular interest include: biosynthesis of vitamin B12; B12-catalyzed enzymatic reactions and their mechanisms; and structural B12-chemistry
Download or read book The Purple Phototrophic Bacteria written by C.N. Hunter and published by Springer Science & Business Media. This book was released on 2008-10-11 with total page 1013 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here is a comprehensive survey of all aspects of these fascinating bacteria, metabolically the most versatile organisms on Earth. It compiles 48 chapters written by leading experts, who highlight the huge progress made in studies of these bacteria since 1995.
Download or read book Statin Associated Muscle Symptoms written by Paul D. Thompson and published by Springer Nature. This book was released on 2020-01-25 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview of statin-associated muscle symptoms (SAMS) from clinical presentation to treatment and possible metabolic causes. It examines the risk factors, presentations, diagnosis and differential diagnosis, clinical management, and financial costs of SAMS. The book also highlights patients’ perspectives on SAMS such as the psychosocial, emotional, and societal factors influencing their perceptions and experiences. Finally, the book presents the results of observational and clinical trials on the prevalence of SAMS, clinical trials for treatments, and potential future research approaches for improving the understanding and treatment of SAMS. A key addition to the Contemporary Cardiology series, Statin-Associated Muscle Symptoms is an essential resource for physicians, medical students, residents, fellows, and allied health professionals in cardiology, endocrinology, pharmacotherapy, primary care, and health promotion and disease prevention.
Download or read book Chemistry and Biochemistry of B12 written by Ruma Banerjee and published by John Wiley & Sons. This book was released on 1999-11-03 with total page 960 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Definitive New Reference for the Latest Advances in B_12 Chemistry and Biochemistry Over the past decade, the field of B_12 research has been revolutionized by such major breakthroughs as the unraveling of the entire biosynthetic pathway for this important vitamin. This comprehensive compendium surveys the wealth of information that has accumulated, covering in one volume virtually all aspects of the field-from physical and inorganic chemistry to enzymology, microbiology, medicine, and diagnostic and therapeutic applications. Edited by Dr. Ruma Banerjee, a highly respected and active member of the B_12 community, this work provides B_12 researchers with a dependable and up-to-date reference on the subject. Leading authorities from five continents explore such new areas as the structural biology of B_12-dependent enzymes, free-radical-mediated reaction mechanisms, biosynthesis, and much more. The role of B_12 in nutrition and disease, and B_12 transport, are also thoroughly examined. Complete with color illustrations and extensive references, Chemistry and Biochemistry of B_12 is a one-of-a-kind resource for biochemists, biophysicists, spectroscopists, microbiologists, molecular biologists, and anyone with an interest in "nature's most beautiful cofactor."
Download or read book Molecular Mechanisms in Bioorganic Processes written by Royal Society of Chemistry (Great Britain). Joint Perkin Division - Bioorganic Group Meeting and published by . This book was released on 1990 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proceedings and lectures from an international symposium on molecular mechanisms and bio-organic processes held at the University of Newcastle-Upon-Tyne, July 1989. Current topics relevant to the title of the symposium are addressed by chemists, biochemists and medical scientists.
Download or read book Introduction to Enzyme and Coenzyme Chemistry written by T. D. H. Bugg and published by John Wiley & Sons. This book was released on 2012-05-29 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enzymes are giant macromolecules which catalyse biochemical reactions. They are remarkable in many ways. Their three-dimensional structures are highly complex, yet they are formed by spontaneous folding of a linear polypeptide chain. Their catalytic properties are far more impressive than synthetic catalysts which operate under more extreme conditions. Each enzyme catalyses a single chemical reaction on a particular chemical substrate with very high enantioselectivity and enantiospecificity at rates which approach “catalytic perfection”. Living cells are capable of carrying out a huge repertoire of enzyme-catalysed chemical reactions, some of which have little or no precedent in organic chemistry. The popular textbook Introduction to Enzyme and Coenzyme Chemistry has been thoroughly updated to include information on the most recent advances in our understanding of enzyme action, with additional recent examples from the literature used to illustrate key points. A major new feature is the inclusion of two-colour figures, and the addition of over 40 new figures of the active sites of enzymes discussed in the text, in order to illustrate the interplay between enzyme structure and function. This new edition provides a concise but comprehensive account from the perspective of organic chemistry, what enzymes are, how they work, and how they catalyse many of the major classes of enzymatic reactions, and will continue to prove invaluable to both undergraduate and postgraduate students of organic, bio-organic and medicinal chemistry, chemical biology, biochemistry and biotechnology.
Download or read book Industrial Biotechnology of Vitamins Biopigments and Antioxidants written by Erick J. Vandamme and published by John Wiley & Sons. This book was released on 2016-04-25 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vitamins are a group of physiologically very important, chemically quite complex organic compounds, that are essential for humans and animals. Some vitamins and other growth factors behave as antioxidants, while some can be considered as biopigments. As their chemical synthesis is laborious, their biotechnology-based synthesis and production via microbial fermentation has gained substantial interest within the last decades. Recent progress in microbial genetics and in metabolic engineering and implementation of innovative bioprocess technology has led to a biotechnology-based industrial production of many vitamins and related compounds. Divided into three sections, this volume covers: 1. water-soluble vitamins 2. fat-soluble vitamin compounds and 3. other growth factors, biopigments, and antioxidants. They are all reviewed systematically: from natural occurrence and assays, via biosynthesis, strain development, to industrially-employed biotechnological syntheses and applications.
Download or read book Comprehensive Chirality written by and published by Newnes. This book was released on 2012-12-31 with total page 5635 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although many books exist on the subject of chiral chemistry, they only briefly cover chiral synthesis and analysis as a minor part of a larger work, to date there are none that pull together the background information and latest advances in one comprehensive reference work. Comprehensive Chirality provides a complete overview of the field, and includes chiral research relevant to synthesis, analytic chemistry, catalysis, and pharmaceuticals. The individual chapters in each of the 9 volumes provide an in depth review and collection of references on definition, technology, applications and a guide/links to the related literature. Whether in an Academic or Corporate setting, these chapters will form an invaluable resource for advanced students/researchers new to an area and those who need further background or answers to a particular problem, particularly in the development of drugs. Chirality research today is a central theme in chemistry and biology and is growing in importance across a number of disciplinary boundaries. These studies do not always share a unique identifying factor or subject themselves to clear and concise definitions. This work unites the different areas of research and allows anyone working or researching in chiral chemistry to navigate through the most essential concepts with ease, saving them time and vastly improving their understanding. The field of chirality counts several journals that are directly and indirectly concerned with the field. There is no reference work that encompasses the entire field and unites the different areas of research through deep foundational reviews. Comprehensive Chirality fills this vacuum, and can be considered the definitive work. It will help users apply context to the diverse journal literature offering and aid them in identifying areas for further research and/or for solving problems. Chief Editors, Hisashi Yamamoto (University of Chicago) and Erick Carreira (ETH Zürich) have assembled an impressive, world-class team of Volume Editors and Contributing Authors. Each chapter has been painstakingly reviewed and checked for consistent high quality. The result is an authoritative overview which ties the literature together and provides the user with a reliable background information and citation resource.
Download or read book Molecular Modelling of Vitamin B12 and Its Analogues written by Penny Govender and published by CRC Press. This book was released on 2021-09-23 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: For many years, the chemistry of vitamin B12 and its derivatives has been investigated for their inherent eco-friendly and nontoxic nature. This vitamin, also known as cobalamin, is an organic complex that contains a cobalt ion in its structure. Its derivatives are vital bio-inorganic cofactors and possess complex and rich photolytic properties, facilitated by their excited states. This book compiles and details cutting-edge research in the application of vitamin B12 as an environmentally benign catalyst for several organic reactions. It discusses the recent advances and current understanding of the photolytic properties of vitamin B12 derivatives from the perspective of the density functional theory (DFT). The book is of interest for anyone involved in nanotechnology, macromolecular science, cancer, and drug-delivery research.
Download or read book Transition Metals in Coordination Environments written by Ewa Broclawik and published by Springer. This book was released on 2019-03-16 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the electronic properties of transition metals in coordination environments. These properties are responsible for the unique and intricate activity of transition metal sites in bio- and inorganic catalysis, but also pose challenges for both theoretical and experimental studies. Written by an international group of recognized experts, the book reviews recent advances in computational modeling and discusses their interplay using experiments. It covers a broad range of topics, including advanced computational methods for transition metal systems; spectroscopic, electrochemical and catalytic properties of transition metals in coordination environments; metalloenzymes and biomimetic compounds; and spin-related phenomena. As such, the book offers an invaluable resource for all researchers and postgraduate students interested in both fundamental and application-oriented research in the field of transition metal systems.
Download or read book Dietary Reference Intakes for Thiamin Riboflavin Niacin Vitamin B6 Folate Vitamin B12 Pantothenic Acid Biotin and Choline written by Institute of Medicine and published by National Academies Press. This book was released on 2000-07-15 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1941, Recommended Dietary Allowances (RDAs) has been recognized as the most authoritative source of information on nutrient levels for healthy people. Since publication of the 10th edition in 1989, there has been rising awareness of the impact of nutrition on chronic disease. In light of new research findings and a growing public focus on nutrition and health, the expert panel responsible for formulation RDAs reviewed and expanded its approachâ€"the result: Dietary Reference Intakes. This new series of references greatly extends the scope and application of previous nutrient guidelines. For each nutrient the book presents what is known about how the nutrient functions in the human body, what the best method is to determine its requirements, which factors (caffeine or exercise, for example) may affect how it works, and how the nutrient may be related to chronic disease. This volume of the series presents information about thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline. Based on analysis of nutrient metabolism in humans and data on intakes in the U.S. population, the committee recommends intakes for each age groupâ€"from the first days of life through childhood, sexual maturity, midlife, and the later years. Recommendations for pregnancy and lactation also are made, and the book identifies when intake of a nutrient may be too much. Representing a new paradigm for the nutrition community, Dietary Reference Intakes encompasses: Estimated Average Requirements (EARs). These are used to set Recommended Dietary Allowances. Recommended Dietary Allowances (RDAs). Intakes that meet the RDA are likely to meet the nutrient requirement of nearly all individuals in a life-stage and gender group. Adequate Intakes (AIs). These are used instead of RDAs when an EAR cannot be calculated. Both the RDA and the AI may be used as goals for individual intake. Tolerable Upper Intake Levels (ULs). Intakes below the UL are unlikely to pose risks of adverse health effects in healthy people. This new framework encompasses both essential nutrients and other food components thought to pay a role in health, such as dietary fiber. It incorporates functional endpoints and examines the relationship between dose and response in determining adequacy and the hazards of excess intake for each nutrient.
