A5042674223- Metal-Catalyzed Oxygenation Mechanisms
- Enzyme-mediated dye degradation
- Electrochemical sensors and biosensors
- Electrochemical Analysis and Applications
- Metal complexes synthesis and properties
- Chemical Reaction Mechanisms
- Biofuel production and bioconversion
- Trace Elements in Health
- Organophosphorus compounds synthesis
- Enzyme Catalysis and Immobilization
- Chemical Synthesis and Reactions
- Catalytic Processes in Materials Science
- Peripheral Artery Disease Management
- Porphyrin Metabolism and Disorders
- Chemical Reactions and Isotopes
- Oxidative Organic Chemistry Reactions
- biodegradable polymer synthesis and properties
- Enzyme Production and Characterization
- Electron Spin Resonance Studies
- Inorganic and Organometallic Chemistry
- Enzyme Structure and Function
- Organic and Inorganic Chemical Reactions
- Fluorine in Organic Chemistry
Stanford University
2015-2023
Taunton & Somerset NHS Foundation Trust
2005
King's College London
1991
Lytic polysaccharide monooxygenases (LPMOs) have been proposed to react with both [Formula: see text] and as cosubstrates. In this study, the reaction reduced Hypocrea jecorina LPMO9A (CuI-HjLPMO9A) is demonstrated be 1,000-fold faster than while producing same oxidized oligosaccharide products. Analysis of reactivity in absence substrate by stopped-flow absorption rapid freeze-quench (RFQ) electron paramagnetic resonance (EPR) magnetic circular dichroism (MCD) yields two intermediates...
For decades, the enzymes of fungus Hypocrea jecorina have served as a model system for breakdown cellulose. Three-dimensional structures almost all H. cellulose-degrading are available, except HjLPMO9A, belonging to AA9 family lytic polysaccharide monooxygenases (LPMOs). These enhance hydrolytic activity cellulases and essential cost-efficient conversion lignocellulosic biomass. Here, using structural spectroscopic analyses, we found that native HjLPMO9A contains catalytic domain family-1...
Lytic polysaccharide monooxygenases (LPMOs) catalyze the degradation of recalcitrant carbohydrate substrates. These enzymes are characterized by a mononuclear Cu(I) active site with three-coordinate T-shaped "His-brace" configuration including N-terminal histidine and its amine group as ligands. This study explicitly investigates electronic structure d10 in LPMO using Kβ X-ray emission spectroscopy (XES). The lack inversion symmetry His-brace enables 3d/p mixing required for intensity...
High potential multicopper oxidases (MCOs) have T1 reduction potentials >600 mV (vs normal hydrogen electrode), making them important catalysts for O2 in various biotechnological applications. The oxygen mechanism the low MCOs is well-characterized; however, reactivity of high not well understood. In this study, we shown that laccase from Trametes versicolor, where redox increased by ∼350 over corresponding to an 8 kcal/mol decrease driving force, exhibits a slower intramolecular electron...
In multicopper oxidases (MCOs), the type 1 (T1) Cu accepts electrons from substrate and transfers these to trinuclear cluster (TNC) where O2 is reduced H2O. The T1 potential in MCOs varies 340 780 mV, a range not explained by existing literature. This study focused on ∼350 mV difference of center Fet3p Trametes versicolor laccase (TvL) that have same 2His1Cys ligand set. A spectroscopies performed oxidized sites shows they equivalent geometric electronic structures. However, two His ligands...
Multicopper oxidases (MCOs) utilize an electron shuttling Type 1 Cu (T1) site in conjunction with a mononuclear 2 (T2) and binuclear 3 (T3) site, arranged trinuclear copper cluster (TNC), to reduce O2 H2O. Reduction of occurs limited overpotential indicating that all the coppers active can be reduced via high-potential donors. Two forms resting enzyme have been observed MCOs: alternative form (AR), where only one three TNC Cu's is oxidized, oxidized (RO), are oxidized. In contrast AR form,...
Unraveling the mechanism of ceruloplasmin (Cp) is fundamentally important toward understanding pathogenesis metal-mediated diseases and metal neurotoxicity. Here we report that Cl–, most abundant anion in blood plasma, a key component Cp catalysis. Based on detailed spectroscopic analyses, Cl– preferentially interacts with partially reduced trinuclear Cu cluster (TNC) under physiological conditions shifts electron equilibrium distribution among two redox active type 1 (T1) sites TNC. This...
Multicopper oxidases (MCOs) are a large family of diverse enzymes found in both eukaryotes and prokaryotes that couple one-electron oxidations various substrates to the four-electron reduction O2 H2O, functioning through set metallocofactors consisting one type 1 copper (T1 Cu) trinuclear cluster (TNC). Human serum ceruloplasmin (Cp) is unique member MCOs composed six cupredoxin domains harbors Cu ions arranged as three T1 TNC. The native substrate Cp Fe2+. It an essential ferroxidase...
The multicopper oxidases (MCOs) couple four 1e– oxidations of substrate to the 4e– reduction O2 H2O. These divide into two groups: those that oxidize organic substrates with high turnover frequencies (TOFs) up 560 s–1 and metal ions low TOFs, ∼1 or less. catalytic mechanism has been elucidated, TOF is achieved through rapid intramolecular electron transfer (IET) native intermediate (NI), which only slowly decays resting form. Here, we uncover factors govern in Fet3p, a prototypical...
The kinetics and mechanism of the elimination sulphuric acid from sulphate ester 2-hydroxy-2-methylpropionamide in 90–102% H2SO4 have been studied by multinuclear (1H, 2H, 13C 15N) NMR spectroscopy. results, which include activation parameters, influence strength kinetic isotope effects, are consistent with an E2 occurring protonated substrate involving hydrogensulphate anion as a base.
Aims: Endovascular aneurysm repair (EVAR) has become an established alternative to open (OR).We present 556 elective patients with infrarenal abdominal aortic aneurysm, comparing OR versus EVAR.Methods: Prospective data collection from 1991 2004 was reviewed.Statistical analysis performed using the SPSS editor χ 2 tests and Mann-Whitney U-test ( * P < 0•05).Results: There were 438 (386 males, 52 females) median age 71 (IQR, 66-75•5) years 118 EVAR (109 9 74 69-79) years.For OR, there 322...
Large normal (kH/kD > 1) secondary deuterium kinetic isotope effects have been observed in E1 and E2 reactions of some steroidal axial trimethylammonium salts when the leaving groups were partly or fully deuteriated; analogous but much smaller 2-phenylethyltrimethyl-ammonium salts.
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