Download or read book Spectroscopic Investigation of the Mechanism of Dioxygen Cleavage in Coupled Binuclear and Trinuclear Copper Models of Enzyme Active Sites written by Mark Jeffrey Henson and published by . This book was released on 2001 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2001 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Studies of Structural and Functional Binuclear Copper Model Complexes of Coupled Binuclear Copper Proteins written by Michael Alan Vance and published by . This book was released on 2007 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic and Theoretical Studies of Electronic Structural Analogues for the Coupled Binuclear Copper Active Site in Hemocyanin and Tyrosinase written by Paul Kevin Ross and published by . This book was released on 1990 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annual Commencement written by Stanford University and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Studies of the Charge Transfer Transitions of the Coupled Binuclear Copper Center in Hemocyanin and Related Model Complexes written by James Edmund Pate and published by . This book was released on 1987 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Copper Oxygen Chemistry written by Kenneth D. Karlin and published by John Wiley & Sons. This book was released on 2011-08-24 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers the vastly expanding subject of oxidative processes mediated by copper ions within biological systems Copper-mediated biological oxidations offer a broad range of fundamentally important and potentially practical chemical processes that cross many chemical and pharmaceutical disciplines. This newest volume in the Wiley Series on Reactive Intermediates in Chemistry and Biology is divided into three logical areas within the topic of copper/oxygen chemistry— biological systems, theory, and bioinorganic models and applications—to explore the biosphere for its highly evolved and thus efficient oxidative transformations in the discovery of new types of interactions between molecular oxygen and copper ion. Featuring a diverse collection of subject matter unified in one complete and comprehensive resource, Copper-Oxygen Chemistry probes the fundamental aspects of copper coordination chemistry, synthetic organic chemistry, and biological chemistry to reveal both the biological and chemical aspects driving the current exciting research efforts behind copper-oxygen chemistry. In addition, Copper-Oxygen Chemistry: Addresses the significantly increasing literature on oxygen-atom insertion and carbon-carbon bond-forming reactions as well as enantioselective oxidation chemistries Progresses from biological systems to spectroscopy and theory, and onward to bioinorganic models and applications Covers a wide array of reaction types such as insertion and dehydrogenation reactions that utilize the cheap, abundant, and energy-containing O2 molecule With thorough coverage by prominent authors and researchers shaping innovations in this growing field, this valuable reference is essential reading for bioinorganic chemists, as well as organic, synthetic, and pharmaceutical chemists in academia and industry.
Download or read book Binuclear Copper dioxygen Complexes written by Viswanath Mahadevan and published by . This book was released on 2001 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanistic Studies of the Multicopper Oxidases written by David Earl Heppner and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Multicopper Oxidases (MCOs) are the family of enzymes that couple the four-electron reduction of dioxygen to water with four 1-electron oxidations of substrates. These enzymes contain a Type 1 (T1) or blue Cu center that is solvent accessible and where substrate is oxidized, reducing this Cu. These electrons are then transferred over a distance of ~13 Å through the protein via a Cys-His pathway to a trinuclear cluster (TNC), composed of a Type 3 Cu pair and a Type 2 Cu, where dioxygen binds and is reduced to water. The mechanism of dioxygen reduction to water by the MCOs is well-characterized and proceeds in two, two-electron steps. The fully reduced enzyme reacts with dioxygen to form the Peroxy Intermediate, where dioxygen is bound as peroxide to the TNC. The O-O bond is cleaved at this point to produce the native intermediate (NI), which is fully oxidized with all three Cu's of the TNC bridged by a central oxo and the T3s are additionally bridged by a hydroxo. Both moieties originate from the 4-electron reduction of dioxygen. This contrasts the resting state where the only bridging ligand is a T3 hydroxo. A long-standing problem concerning the catalytic mechanism of the MCOs was the process by which these enzymes are rereduced in the catalytic cycle. Specifically, Rhus vernicifera Laccase exhibits a turnover rate of 560 s-1 while the intramolecular electron transfer (IET) from the T1 to the TNC of the resting state of this enzyme has been measured to be 1.1 s-1 and therefore not consistent with turnover. We have now experimentally determined that the reduction of NI by ET from the T1 is fast relative to its decay and obtained an IET rate lower-limit of> 700 s-1 for the first electron reduction. Thus proves that NI is the catalytically relevant fully oxidized form of the MCOs; not the fully oxidized resting formed as studied crystallographically. Thus, the first IET rate in NI reduction is more than three orders of magnitude faster than the IET rate in the resting oxidized state. Computations show that this rate difference derives from a larger driving force for proton-coupled electron transfer in NI compared to the resting state due to the strong basicity of the central oxo of NI, where the resting TNC site lacks a strongly basic ligand. In addition to the first IET, there are two remaining IET steps in the reduction of NI to the fully reduced state to complete the catalytic cycle. Kinetic analysis shows that the second IET step is reversible (K H"1), the third is irreversible and both are fast with lower-limits of> 500 s-1. A signal is observed in freeze quench EPR that corresponds to the 1 electron hole intermediate (two electron reduced NI). Kinetic and spectroscopic results coupled to DFT calculations reveal the mechanism of the 3 electron / 3 proton reduction of NI, where all three catalytically relevant intramolecular electron transfer (IET) steps are rapid and involve three different structural changes. The first IET process is a concerted electron and proton transfer (EPT) process made rapid due to the driving force supplied by the protonation of the basic central oxo of NI. The Second IET has a low driving force, but also a low reorganization energy due to a proton transfer / electron transfer stepwise process. The third IET is a concerted EPT process but in this case driven by the extrusion of product waters from the fully reduced TNC. These three rapid IET processes reflect the sophisticated mechanistic flexibility of the TNC to enable rapid turnover. Importantly, all three of these IET steps are rapid because of the basicity of the dioxygen-derived ligands that arise from O-O bond cleavage. In catalysis, the TNC performs the four-electron reduction of dioxygen to the water level in the formation of NI, but only after NI is fully reduced are the water products of dioxygen reduction fully formed and extruded from the cluster to enable reduction of another equivalent of dioxygen. This defines a unifying catalytic mechanism for the MCOs where O-O bond cleavage and three rapid IETs are coupled to enable fast turnover in oxidation catalysis.
Download or read book Multi copper Oxidases written by Albrecht Messerschmidt and published by World Scientific. This book was released on 1997 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: The biological activation of dioxygen is a key reaction in biological systems. Enzymes involved in direct oxygen activation are oxidases and oxygenases. Multi-copper oxidases are an important class of oxidases reducing dioxygen in a four-electron reduction to water with concomitant one-electron oxidation of the reducing substrate. The progress in the characterization and understanding of the structure and function of these enzymes has advanced so tremendously over the last ten years that the publication of a book documenting these achievements has been overdue.Especially the recent discovery of a key role of the FET3 protein of Saccharomyces cerevisae, a multi-copper oxidase, in iron metabolism of this eukaryote has underpinned the function of the plasma multi-copper oxidase ceruloplasmin in vetebrate iron transport. The lately determined x-ray structure of human ceruloplasmin confirms its close structural relatedness to the plant multi-copper oxidases ascorbate oxidase and laccase and due to strong amino-acid sequence similarities has allowed to construct a useful model of the more distantly related blood-clotting factor VIII.This book contains review articles from experts in the field, dealing with modern spectroscopy, enzyme kinetics, bioinorganic chemistry, x-ray crystallography, electron transfer reactions, molecular biology, medical aspects and potential industrial applications of the three main members of multi-copper oxidases, i.e., laccase, ascorbate oxidase and ceruloplasmin.
Download or read book Characterization and Mechanistic Investigations of Model Complexes Relevant to Binuclear and Multinuclear Copper Enzymes written by Liviu M. Mirica and published by . This book was released on 2005 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Studies of Chemically Modified Active Sites in Binuclear Copper Proteins written by Richard Scott Himmelwright and published by . This book was released on 1979 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Studies of Peroxide bridged Binuclear Copper II Complexes Relevant to Oxyhemocyanin and Oxytyrosinase written by Michael Joseph Baldwin and published by . This book was released on 1992 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Investigation of the Multicopper Oxidases written by Liliana Quintanar Vera and published by . This book was released on 2004 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Investigation of Oxygen Intermediates and Ligand Bound Forms of Multicopper Oxidases written by Uma Maheswari Sundaram and published by . This book was released on 1997 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Faculties Publications and Doctoral Theses in Chemistry and Chemical Engineering at United States Universities written by American Chemical Society. Committee on Professional Training and published by . This book was released on 1991 with total page 1646 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic and Theoretical Studies of Copper oxygen Intermediates in Enzyme Model Complexes and Zeolites written by Julia Salas Woertink and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Copper-oxygen species catalyze a wide range of biologically and catalytically relevant reactions. In this dissertation a combined spectroscopic and theoretical approach is used to define the geometric and electronic structure of two copper-oxygen intermediates proposed to be activated for H-atom abstraction: an end-on bound mononuclear cupric-superoxo and a zeolitic site activated for methane monooxygenation.
