Download or read book The Structure and Reactivity of Non heme Iron III Proteins and Model Complexes written by Bruce Prentiss Murch and published by . This book was released on 1987 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Structural Study of Iron III Complexes written by Raju V. Thundathil and published by . This book was released on 1976 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Iron oxo Complexes written by Cheryl A. Christmas and published by . This book was released on 1993 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Iron II Models of Non heme Iron Proteins and Their Reactivity with Dioxygen written by Sonha Christine Payne and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Iron containing Enzymes written by Sam P. De Visser and published by Royal Society of Chemistry. This book was released on 2011 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mononuclear iron containing enzymes are important intermediates in bioprocesses and have potential in the industrial biosynthesis of specific products. This book features topical review chapters by leaders in this field and its various sub-disciplines.

Download or read book Iron Carriers and Iron Proteins written by Thomas M. Loehr and published by Wiley-VCH. This book was released on 1989 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spectroscopic and Theoretical Studies of Complexes which Model the Active Sites of Non heme Iron Proteins written by Carl A. Brown and published by . This book was released on 1994 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Steric Effects on the Stability and Reactivity of Model Complexes of Non heme Diiron Proteins and Ferritin written by Do Trong Bao and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nitrosyl Complexes in Inorganic Chemistry Biochemistry and Medicine II written by D. Michael P. Mingos and published by Springer. This book was released on 2014-06-19 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Structure and Bonding publishes critical reviews on topics of research concerned with chemical structure and bonding. The scope of the series spans the entire Periodic Table and addresses structure and bonding issues associated with all of the elements. It also focuses attention on new and developing areas of modern structural and theoretical chemistry such as nanostructures, molecular electronics, designed molecular solids, surfaces, metal clusters and supramolecular structures. Physical and spectroscopic techniques used to determine, examine and model structures fall within the purview of Structure and Bonding to the extent that the focus is on the scientific results obtained and not on specialist information concerning the techniques themselves. Issues associated with the development of bonding models and generalizations that illuminate the reactivity pathways and rates of chemical processes are also relevant. The individual volumes in the series are thematic. The goal of each volume is to give the reader, whether at a university or in industry, a comprehensive overview of an area where new insights are emerging that are of interest to a larger scientific audience. Thus each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years should be presented using selected examples to illustrate the principles discussed. A description of the physical basis of the experimental techniques that have been used to provide the primary data may also be appropriate, if it has not been covered in detail elsewhere. The coverage need not be exhaustive in data, but should rather be conceptual, concentrating on the new principles being developed that will allow the reader, who is not a specialist in the area covered, to understand the data presented. Discussion of possible future research directions in the area is welcomed. Review articles for the individual volumes are invited by the volume editors. Readership: research scientists at universities or in industry, graduate students Special offer for all customers who have a standing order to the print version of Structure and Bonding, we offer free access to the electronic volumes of the Series published in the current year via SpringerLink.

Download or read book The Physiology of Microalgae written by Michael A. Borowitzka and published by Springer. This book was released on 2016-03-21 with total page 673 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the state-of-the-art of microalgae physiology and biochemistry (and the several –omics). It serves as a key reference work for those working with microalgae, whether in the lab, the field, or for commercial applications. It is aimed at new entrants into the field (i.e. PhD students) as well as experienced practitioners. It has been over 40 years since the publication of a book on algal physiology. Apart from reviews and chapters no other comprehensive book on this topic has been published. Research on microalgae has expanded enormously since then, as has the commercial exploitation of microalgae. This volume thoroughly deals with the most critical physiological and biochemical processes governing algal growth and production.

Download or read book Dietary Reference Intakes for Vitamin A Vitamin K Arsenic Boron Chromium Copper Iodine Iron Manganese Molybdenum Nickel Silicon Vanadium and Zinc written by Institute of Medicine and published by National Academies Press. This book was released on 2002-07-19 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is the newest release in the authoritative series issued by the National Academy of Sciences on dietary reference intakes (DRIs). This series provides recommended intakes, such as Recommended Dietary Allowances (RDAs), for use in planning nutritionally adequate diets for individuals based on age and gender. In addition, a new reference intake, the Tolerable Upper Intake Level (UL), has also been established to assist an individual in knowing how much is "too much" of a nutrient. Based on the Institute of Medicine's review of the scientific literature regarding dietary micronutrients, recommendations have been formulated regarding vitamins A and K, iron, iodine, chromium, copper, manganese, molybdenum, zinc, and other potentially beneficial trace elements such as boron to determine the roles, if any, they play in health. The book also: Reviews selected components of food that may influence the bioavailability of these compounds. Develops estimates of dietary intake of these compounds that are compatible with good nutrition throughout the life span and that may decrease risk of chronic disease where data indicate they play a role. Determines Tolerable Upper Intake levels for each nutrient reviewed where adequate scientific data are available in specific population subgroups. Identifies research needed to improve knowledge of the role of these micronutrients in human health. This book will be important to professionals in nutrition research and education.

Download or read book Bioinorganic Chemistry Volume 38 written by Stephen J. Lippard and published by John Wiley & Sons. This book was released on 2009-09-17 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive series of volumes on inorganic chemistry provides inorganic chemists with a forum for critical, authoritative evaluations of advances in every area of the discipline. Every volume reports recent progress with a significant, up-to-date selection of papers by internationally recognized researchers, complemented by detailed discussions and complete documentation. Each volume features a complete subject index and the series includes a cumulative index as well.

Download or read book High valent Oxygen Intermediates of Mononuclear Non heme Iron Enzymes written by Shaun Di Hang Wong and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mononuclear non-heme iron (NHFe) enzymes catalyze a wide variety of biologically-important reactions such as hydroxylation, halogenation, desaturation, ring closure, and electrophilic aromatic substitution. The key intermediate in the catalytic cycle is the S = 2 Fe(IV)=O species, capable of abstracting an H-atom from inert C--H bonds as strong as 106 kcal/mol. The Fe(IV)=O intermediate in enzymes is transient and difficult to trap; as such, stable synthetic analogs have proven invaluable for spectroscopic elucidation of the geometric/electronic structure of the Fe(IV)=O unit and how it is activated for reactivity. Such biomimetic Fe(IV)=O model complexes can be either intermediate-spin (S = 1) or high-spin (S = 2) in contrast to the S = 2 ground state of enzyme intermediates. For an S = 1 Fe(IV)=O species, the Fe--oxo [beta] [pi]*-frontier molecular orbital (FMO) [from the combination of Fe d(xz/yz) and oxo p(x/y)] is involved in H-atom abstraction, and this FMO requires a side-on approach ([pi]-attack) to achieve maximum overlap with the substrate C--H bond. Through magnetic circular dichroism (MCD) and nuclear vibrational resonance spectroscopy (NRVS) studies, the reactivity of the S = 1 Fe(IV)=O unit has been shown to be affected by the oxo contribution in the [pi]*-FMO, where a larger oxo contribution results in greater orbital overlap (with the substrate C--H) and higher reactivity; also, the [pi]-attack pathway results in steric clashes between substrate and ligand, giving a significant steric contribution to the energy of the reaction barrier. For an S = 2 Fe(IV)=O species, the Fe--oxo [alpha] [sigma]*-FMO [Fe d(z2) and oxo p(z)] is spin-polarized (exchange-stabilized) to an energy level comparable with its [pi]*-FMO, making it accessible as a second pathway ([sigma]-attack) for reactivity. In the S = 2 Fe(IV)=O model complex ligated by TMG3tren, this [sigma]*-FMO is active but is axially hindered by the ligand, again giving a large steric contribution to the reaction barrier; however, the intrinsic electronic reaction barriers of the S = 2 [sigma]*-FMO and the S = 1 [pi]*-FMO are comparable, suggesting they are similarly active in H-atom abstraction. Furthermore, MCD excited-state spectroscopy in combination with multiconfigurational calculations on the S = 2 model reveal two different [pi]-pathways for reactivity involving Fe(III)--oxyl[p(x), [pi]] character, in addition to the [sigma]-pathway involving Fe(III)--oxyl[p(z), [sigma]] character, showing that the S = 2 Fe(IV)=O unit is activated for both [pi] and [sigma] H-atom abstraction reactivities. Finally, the S = 2 enzyme intermediate for the halogenase SyrB2 was trapped and structurally characterized by NRVS, revealing two possible 5-coordinate trigonal bipyramidal candidates with the Fe--oxo vector oriented either perpendicular or parallel to the substrate C--H bond. Importantly, this difference in orientation leads to Fe(III)--OH products oriented efficiently for different rebound reactivities -- native halogenation in the case of perpendicular orientation and non-native hydroxylation in the case of parallel orientation.

Download or read book Biomimetic Oxidations Catalyzed By Transition Metal Complexes written by Bernard Meunier and published by World Scientific. This book was released on 2000-03-08 with total page 697 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the classic work Metal-Catalyzed Oxidations of Organic Compounds (edited by R A Sheldon and J K Kochi, 1991), no book has been devoted to advances in the field of biomimetic oxidations, which was created nearly 18 years ago. This expanding research field is covered in this volume. All the different aspects of the modeling of oxidations catalyzed by metalloenzymes are dealt with.This invaluable book will be useful to postgraduates as well as researchers in academia and industry, and will also benefit second year university students.

Download or read book Diabetes written by Victor R Preedy and published by Academic Press. This book was released on 2020-04-24 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diabetes: Oxidative Stress and Dietary Antioxidants, Second Edition, builds on the success of the first edition, covering updated research on the science of oxidative stress in diabetes and the potentially therapeutic usage of natural antioxidants in the diet and food matrix. The processes within the science of oxidative stress are not described in isolation, but rather in concert with other processes, such as apoptosis, cell signaling and receptor mediated responses. This approach recognizes that diseases are often multifactorial and oxidative stress is a single component of this. Since the publication of the first edition, the science of oxidative stress and free radical biology continues to rapidly advance with thousands of the research articles on the topic. New sections in this update cover the role of dietary advanced glycation end products (AGEs) in causing OS in diabetes, oxidative stress and diabetes-induced bone metabolism, and oxidative stress and diabetic foot ulcer. Saves clinicians and researchers time in quickly accessing the very latest details on a broad range of diabetes and oxidation issues Combines the science of oxidative stress and the putative therapeutic usage of natural antioxidants in the diet, its food matrix or plant Includes preclinical, clinical and population studies to help endocrinologists, diabetologists, nutritionists, dieticians and clinicians map out key areas for research and further clinical recommendations

Download or read book Bioinorganic Spectroscopy Structure function Correlations in Binuclear Non heme Iron Enzymes and Developing Nuclear Resonance Vibrational Spectroscopy for Characterization of Enzyme Intermediates written by Caleb Branson Bell and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The foci of this dissertation are: 1) combined use of spectroscopies for mechanistic understanding of the oxygen reactions of various non-heme iron enzymes and related model complexes, and 2) the development of the recently described nuclear vibrational resonance spectroscopy (NRVS) coupled with density functional calculations (DFT) for characterization of non-heme iron enzyme intermediates. Binuclear non-heme iron enzymes are involved in many medically and industrially important processes such as DNA synthesis by ribonucleotide reductase (RNR), conversion of methane to methanol by methane monooxygenase (MMO), fatty acid desaturation by [Delta]9 desaturase, iron storage and homeostasis by ferritins, degradation of aromatic compounds by various bacterial monooxygenases (ToMO, T4MO, etc.) and antibiotic biogenesis by p-aminobenzoate N-oxygenase (AurF), etc. Interestingly, these diverse reactions typically begin with O2 reacting with a biferrous active site, coordinated by highly conserved protein ligands (ExxH motifs) in four [Alpha]-helix bundles. Moreover, spectroscopically and chemically similar intermediates can be detected in many of the enzyme systems. The best studied in this family are RNRs, where biferric peroxo intermediates (P and P'), and the high-valent Fe(III)Fe(IV) intermediate X have been stabilized and spectroscopically characterized in wt and numerous variants. De novo designed four [Alpha]-helix bundles have been synthesized (the ~140 amino acid dui ferri (DF) peptide family) and are good models for binuclear non-heme iron enzymes. These systems provide a protein environment and can be viewed as a bridge between inorganic model complexes and native proteins. The pseudo-symmetric single chain version (DFsc) coordinates two ferrous ions by two His and four Glu amino acid residues. Circular dichroism (CD), magnetic CD (MCD) and variable-temperature variable-field MCD (VTVH MCD) show that this "active site" in DFsc has a 4-coordinate and 5-coordinate (4C+5C) geometry that is weakly antiferromagnetically coupled (J [approximately equal to] --2 cm-1) indicative of [Mu]1,3 carboxylate bridges, highly similar to RNR biferrous structures. Extended x-ray absorption fine structure (EXAFS) data are consistent with this assignment and show that one terminal carboxylate residue coordinates in a bidentate fashion. Changes in the CD/MCD/VTVH MCD and EXAFS spectra in the Y51L and E11D variants show that the 4C site is proximal to (but not bound by) Y51 and the bidentate carboxylate is coordinated to the 5C iron. Open coordination positions on both irons allow for dioxygen to react rapidly with the biferrous site. The reaction of biferrous DFsc with dioxygen yields a 520 nm ([Epsilon] = [weak approximation to]1200 M-1cm-1) species with a formation rate of 2 s-1, again similar to RNR (the Class Ia RNR from Escherichia coli has a dioxygen reaction rate of ~1 s-1, however the first species formed (intermediate P) has [Lambda]max = 700 nm). The resonance Raman (rR) spectrum obtained by excitation into the 520 nm feature in DFsc (and the E11D variant) proves this chromophore arises from a Tyr to ferric charge transfer (CT) transition. The 520 nm feature is lost by substitution of Y51 but not Y18, thus Y51 binds to the site after reaction with dioxygen. Subsequent binding of Y51 functions as an internal spectral probe of the dioxygen reaction and as a proton source that would promote loss of hydrogen peroxide. Coordination by a ligand that functions as a proton source could be a structural mechanism used by natural binuclear iron enzymes to drive their reactions past peroxo biferric level intermediates. RNR's can be divided into 3 major classes based on the radical generating machinery. Class I RNR's utilize a dimetal cofactor that reacts with dioxygen and can be subdivided into Classes Ia, Ib and Ic based on sequence homology and metal dependency. Class Ia enzymes are the best studied an present in higher organisms including human (host) while Class Ib enzymes are typically found in pathogens. CD, MCD and VTVH MCD data on biferrous loaded Class Ib RNR from Bacillus cereus allow assignment of the active site as 4C+5C in solution, resolving discrepancies from available crystal structures. Differences in the zero-field splitting parameters (D and E) and magnetic coupling extracted from fits to the VTVH MCD data can be ascribed to differences in the bridging carboxylate conformations. FeII loading, monitored by CD, shows cooperative binding with Kd 100 mM, significantly stronger that the metal binding in Class Ia. This provides the pathogen a competitive advantage relative to host in physiological, iron-limited environments Returning to Class Ia, the recently discovered intermediate P' notably lacks structural definition. This is mainly due to the lack of spectroscopic handles from which to obtain the needed experimental data. What is know, however, is that this species directly forms intermediate X and is directly derived from the well-defined intermediate P. Spectroscopically, P' has Mössbauer isomer shifts ([lowercase Delta] = 0.52 and 0.45 mm/s) that are significantly lower than the cis-[Mu]1,2 peroxo P ([lowercase Delta] = 0.63 mm/s) and lacks the ~700 nm peroxo to ferric CT suggesting some change in coordination mode or protonation may be involved in P -- P'. Comparisons of the reduced and oxidized crystal structures show differences in carboxylate coordination modes and water binding that must occur at some stage along the reaction coordinate. All of these potential structural perturbations were systematically incorporated into computational models of the intermediate site and correlated with experimental data using density functional theory (DFT). Two potential reaction pathways consistent with available experimental data were found. The first involves water addition to Fe1 of the cis-[Mu]-1,2 peroxo intermediate P causing opening of a bridging carboxylate to form intermediate P' which has an increased electron affinity and is activated for proton-coupled electron transfer to form the Fe(III)Fe(IV) intermediate X. While the second, more energetically favorable pathway, involves addition of a proton to a terminal carboxylate ligand in the site which increases the electron affinity and triggers electron transfer to form X. Vibrational characterization could, in principle, distinguish these pathways. However, the lack of a reasonably intense chromophore precludes rR experiments. The recently available method of nuclear vibrational resonance spectroscopy (NRVS) does not have these chromophoric constraints and can provide the needed vibrational data for P'--and many other "spectroscopically challenged" intermediates in non-heme iron biochemistry. The vibrations enhanced in NRVS are typically lower in energy and differ from those observed in rR, thus studies on well defined model complexes are needed prior to intermediate studies. A series of mononuclear Fe(IV)=O have been characterized by NRVS coupled with DFT calculations to define NRVS spectral assignments and set a foundation for vibrational characterization of non-heme iron enzyme intermediates. These studies show that the NRVS spectrum is rich in structural information. Of the four Fe(IV)=O models, supported by the 1, 4, 8, 11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TMC); N, N-bis(2-pyridylmethyl)-N-bis(2-pyridyl) methylamine (N4Py); N-benzyl-N, N', N'-tris(2-pyridylmethyl)-1,2-diaminoethane (BnTPEN); and 1,1,1-tris{2-[N(2)-(1,1,3,3-tetramethylguanidino)]ethyl}amine (TMG3tren) ligand sets, only the trigional bipyramidal geometry (relative to the 6C approximatly C4v geometry of TMC, N4Py and BnTPEN) enforced by the TMG3tren ligand affords a high-spin species. Isotope sensitive Fe-O stretches are observed for all complexes at 820 to 831 cm-1. However, at lower energy (

Download or read book Non Heme Iron iii and Gold iii Complexes with Dicarboxamide Ligands written by Sau-Han Chan and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Non-heme Iron(III) and Gold(III) Complexes With Dicarboxamide Ligands: Synthesis, Structures and Anti-cancer Properties" by Sau-han, Chan, 陳秀嫻, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled NON-HEME IRON(III) AND GOLD(III) COMPLEXES WITH DICARBOXAMIDE LIGANDS: SYNTHESIS, STRUCTURES AND ANTI-CANCER PROPERTIES Submitted by Chan Sau Han For the degree of Doctor of Philosophy at The University of Hong Kong in October 2007 A series of non-heme iron and gold complexes with newly developed dicarboxamide ligands including symmetric [(9,10-bis(pyridine-2-carboxamido) phenanthrene (H bpph) and 3,4-bis(pyridine-2-carboxamido)thiophene (H bpth)] and 2 2 asymmetric ones [2,3-bis(pyridine-2-carboxamido)pyridine (H bppy), 3,4-bis(pyridine-2-carboxamido)methoxybenzene (H bpmb), 3,4-bis(pyridine-2- carboxamido)nitrobenzene (H bpnb), 3,4-bis(pyridine-2-carboxamido)benzophenone (H bpap), 3,4-bis(pyridine-2-carboxamido-5-n-butyl)benzophenone (H bbpap), 2 2 3,4-bis(pyridine-2-carboxamido)methyl benzoate (H bpmo), 3,4-bis(pyridine-2- carboxamido)benzoic acid (H bpac), 3,4-bis(pyridine-2-carboxamido-3-benzoyl)- benzophenone (H bzpap)] were prepared; their spectroscopic and structural properties and biological activities were examined. Magnetic susceptibility measurements III n revealed that [R N][Fe (L)(R'COO) ] [R = Et, Bu; L = bpap, bbpap; R' = CH, C H, 4 2 3 6 5 n III CF, CF CF CF ) and [ Bu N][Fe (L)Cl ] (L = bpth, bpap) are high-spin compounds 3 3 2 2 4 2 with of 5.174-6.116. Electrochemical reductions of dicarboxamide ferric eff +/0 complexes occurred in the range of E -0.60 to -0.91 V (vs Cp Fe ), and were 1/2 2 attributed to metal-centered reductions. III Comparative crystallographic analyses of [R N][Fe (L)(R'COO) ] (19: R = Et, L = 4 2 bpap, R' = CH; 21: R = Bu, L = bpap, R' = C H; 26: R = Et, L = bbpap, R' = CH ) 3 6 5 3 bearing asymmetric ligands revealed a reversal of C-O distance change: the C-O(free) distances are longer than those of C-O(binding) (by up to 0.255 A). X-ray crystal structures also showed that the reversal of C-O distance change is likely to result from a subtle change of crystal lattice environment and stabilization by cooperative weak interactions among the axial carboxylate groups and various surrounding C-H hydrogen bond donors. Cytotoxicity studies of dicarboxamide iron(III) and gold(III) complexes using various human cell lines, including cervical epithelial carcinoma cells (HeLa), hepatocellular carcinoma cells (HepG2), nasopharyngeal carcinoma cells (SUNE1), III and normal lung fibroblasts (CCD-19Lu), revealed that [Et N][Fe (bpc)(CH COO) ] 4 3 2 n III III III (4), [ Bu N][Fe (bpap)Cl ] (20), Au (bpap)Cl (41) and Au (bbpap)Cl (42) have high 4 2 cytotoxicity (IC = 10-21 M) and selectivity toward certain cancer cells (3 to 6-fold). 50 Complex 20 exhibited the highest cytotoxicity, with IC values ranging from 10 M to 50 60 M, and was 6-fold more cytotoxic in HepG2 cancer cells than in normal CCD-19Lu cells. This complex induced nicking of supercoiled plasmid DNA. Treatment of cells with 20 also stimulated production of intracellular reactive oxygen species (ROS), as revealed by the studies using the fluorescence probe dihydrorhodamine-123. Complex 20 also induced cell death characteristic of apoptosis, namely, cleavage of PARP and caspase-3, -7 and -9, increased Bax expression and decreased Bcl-xL expression. The gold(III) complexes, 41 and 42, were found to bind ii to DNA. The