Towards an Understanding of the Chemistry of Oxygen Reduction

1995 ◽  
Vol 22 (3) ◽  
pp. 479 ◽  
Author(s):  
PR Rich
Keyword(s):  
Oxygen Reduction ◽  
Proton Translocation ◽  
Essential Elements ◽  
Catalytic Cycle ◽  
Terminal Oxidases ◽  
Working Model ◽  
Catalytic Intermediates

Advances in understanding of the structure and the catalytic cycle of oxygen reduction of the protonmotive haem-copper terminal oxidases are reviewed. This information has been combined with our recent recognition of the need for electroneutrality of stable catalytic intermediates to produce a new working model of the essential elements of the chemiosmotic mechanism of coupling of oxygen reduction chemistry to vectorial proton translocation.

pH Dependence of Proton Translocation in the Oxidative and Reductive Phases of the Catalytic Cycle of CytochromecOxidase. The Role of H2O Produced at the Oxygen-Reduction Site†

Biochemistry ◽  
2006 ◽  
Vol 45 (6) ◽  
pp. 1930-1937 ◽  
Author(s):  
Giuseppe Capitanio ◽  
Pietro Luca Martino ◽  
Nazzareno Capitanio ◽  
Emanuele De Nitto ◽  
Sergio Papa
Keyword(s):  
Oxygen Reduction ◽  
Ph Dependence ◽  
Proton Translocation ◽  
Catalytic Cycle

Oxygen Reduction and Proton Translocation by the Heme-Copper Oxidases

1999 ◽  
pp. 193-217 ◽  
Author(s):  
Mårten Wikström ◽  
Joel E. Morgan ◽  
Gerhard Hummer ◽  
William H. Woodruff ◽  
Michael I. Verkhovsky
Keyword(s):  
Oxygen Reduction ◽  
Proton Translocation ◽  
Heme Copper Oxidases

scholarly journals Discovery of the True Peroxy Intermediate in the Catalytic Cycle of Terminal Oxidases by Real-time Measurement

2007 ◽  
Vol 282 (39) ◽  
pp. 28514-28519 ◽  
Author(s):  
Ilya Belevich ◽  
Vitaliy B. Borisov ◽  
Michael I. Verkhovsky
Keyword(s):  
Real Time ◽  
Time Measurement ◽  
Catalytic Cycle ◽  
Terminal Oxidases ◽  
Real Time Measurement

The Terminal Oxidase in the Marine Bacterium Pseudomonas nautica 617

1997 ◽  
Vol 17 (3) ◽  
pp. 343-346 ◽  
Author(s):  
Helen Simpson ◽  
Michel Denis ◽  
Francesco Malatesta
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Monoxide ◽  
Oxygen Reduction ◽  
Epr Spectroscopy ◽  
Marine Bacterium ◽  
Large Family ◽  
Terminal Oxidase ◽  
Quinol Oxidase ◽  
Terminal Oxidases ◽  
Production Of Hydrogen

The molecular properties of a novel membrane quinol oxidase from the marine bacterium Pseudomonas nautica 617 are presented. The protein contains 2b hemes/mole which may be distinguished by EPR spectroscopy but not by optical spectroscopy and electrochemistry. Respiration, though being cyanide insensitive, is not inhibited by carbon monoxide and oxygen reduction is carried out only half-way with production of hydrogen peroxide. The terminal oxidase represents, therefore, a unique example in the large family of terminal oxidases known up to date.

scholarly journals Elementary steps of proton translocation in the catalytic cycle of cytochrome oxidase

2006 ◽  
Vol 1757 (5-6) ◽  
pp. 401-407 ◽  
Author(s):  
Michael I. Verkhovsky ◽  
Ilya Belevich ◽  
Dmitry A. Bloch ◽  
Mårten Wikström
Keyword(s):  
Cytochrome Oxidase ◽  
Proton Translocation ◽  
Catalytic Cycle ◽  
Elementary Steps

scholarly journals [CoII(BPyPy2COH)(OH2)2]2+: A Catalytic Pourbaix Diagram and AIMD Simulations on Four Key Intermediates

2019 ◽  
Vol 73 (11) ◽  
pp. 906-912
Author(s):  
Roger Alberto ◽  
Marcella Iannuzzi ◽  
Yeliz Gurdal ◽  
Benjamin Probst
Keyword(s):  
Aqueous Solution ◽  
Catalytic Cycle ◽  
Acidic Ph ◽  
Proton Reduction ◽  
Pourbaix Diagram ◽  
Time Resolved ◽  
Proton Coupled Electron Transfer ◽  
Catalytic Intermediates ◽  
Ph Dependent ◽  
Dynamics Simulations

Proton reduction by [CoII(BPyPy2COH)(OH2)2]2+ (BPyPy2COH = [2,2'-bipyridin]-6-yl-di[pyridin-2-yl]methanol) proceeds through two distinct, pH-dependent pathways involving proton-coupled electron transfer (PCET), reduction and protonation steps. In this account we give an overview of the key mechanistic aspects in aqueous solution from pH 3 to 10, based on electrochemical data, time-resolved spectroscopy and ab initio molecular dynamics simulations of the key catalytic intermediates. In the acidic pH branch, a PCET to give a CoIII hydride is followed by a reduction and a protonation step, to close the catalytic cycle. At elevated pH, a reduction to CoI is observed, followed by a PCET to a CoII hydride, and the catalytic cycle is closed by a slow protonation step. In our simulation, both CoI and CoII–H feature a strong interaction with the surrounding solvent via hydrogen bonding, which is expected to foster the following catalytic step.

scholarly journals Intermediates in the catalytic cycle of lentil (Lens esculenta) seedling copper-containing amine oxidase1

1998 ◽  
Vol 332 (2) ◽  
pp. 431-437 ◽  
Author(s):  
Rosaria MEDDA ◽  
Alessandra PADIGLIA ◽  
Andrea BELLELLI ◽  
Paolo SARTI ◽  
Stefano SANTANCHÈ ◽  
...  
Keyword(s):  
Chemical Nature ◽  
Amine Oxidase ◽  
Ph Dependence ◽  
Equilibrium Mixture ◽  
Order Rate Constant ◽  
Catalytic Cycle ◽  
Reduced Form ◽  
Lens Esculenta ◽  
Catalytic Intermediates ◽  
Absorbance Changes

Spectrophotometry and rapid-scanning stopped-flow spectroscopy have been used to investigate the visible absorbance changes that occur in the course of the reduction of lentil (Lens esculenta) seedling amine oxidase by substrate. The catalytic cycle of the enzyme employs several intermediates but, owing to kinetic limitations, some of them were not identified in previous studies. In this study we have examined several substrates, either rapidly reacting (e.g. putrescine) or slowly reacting (e.g. γ-aminobutanoic acid). Two forms of the enzyme, namely the Cu(I)-aminoresorcinol and quinone ketimine derivatives, whose characterization was elusive in previous studies, have been identified and assigned an optical spectrum. Moreover the reduced form of the enzyme is shown to be an equilibrium mixture of two species, the Cu(I)-semiquinolamine radical and Cu(II)-aminoresorcinol; these have been resolved by pH dependence and assigned spectra as well as a second-order rate constant for the reaction with oxygen. Thus the results presented here identify all the catalytic intermediates suggested by the chemical nature of the coenzyme and define their spectroscopic and reactivity properties.

scholarly journals Proton translocation by cytochrome c oxidase in different phases of the catalytic cycle

2002 ◽  
Vol 1555 (1-3) ◽  
pp. 128-132 ◽  
Author(s):  
Mårten Wikström ◽  
Michael I Verkhovsky
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Proton Translocation ◽  
Catalytic Cycle

Respiratory Protection of Nitrogenase Activity in Azotobacter vinelandii—Roles of the Terminal Oxidases

1997 ◽  
Vol 17 (3) ◽  
pp. 303-317 ◽  
Author(s):  
Robert K. Poole ◽  
Susan Hill
Keyword(s):  
Gene Expression ◽  
Nitrogen Fixation ◽  
Oxygen Reduction ◽  
Crucial Role ◽  
Azotobacter Vinelandii ◽  
Nitrogenase Activity ◽  
Terminal Oxidase ◽  
Respiratory Protection ◽  
Terminal Oxidases ◽  
Cytochrome Bd

Nitrogen fixation by aerobic prokaryotes appears paradoxical: the nitrogen-fixing enzymes—nitrogenases—are notoriously oxygen-labile, yet many bacteria fix nitrogen aerobically. This review summarises the evidence that cytochrome bd, a terminal oxidase unrelated to the mitochondrial and many other bacterial oxidases, plays a crucial role in aerotolerant nitrogen fixation in Azotobacter vinelandii and other bacteria by rapidly consuming oxygen during uncoupled respiration. We review the pertinent properties of this oxidase, particularly its complement of redox centres, the catalytic cycle of oxygen reduction, the affinity of the oxidase for oxygen, and the regulation of cytochrome bd gene expression. The roles of other oxidases and other mechanisms for limiting damage to nitrogenase are assessed.

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