The one-electron oxidation of duplex DNA generates a nucleobase radical cation (electron "hole") that migrates long distances by a hopping mechanism. The radical cation reacts irreversibly with H2O or O2 to form oxidation products (damaged bases). In normal DNA (containing the four common DNA bases), reaction occurs most frequently at guanine. However, in DNA duplexes that do not contain guanin...

The spectroscopic and kinetic characterization of two intermediates from the H₂O₂ oxidation of three dimethyl ester [(proto), (meso), (deuteroporphyrinato) (picdien)]Fe(III) complexes ([FePPPic], [FeMPPic] and [FeDPPic], respectively) pinch-porphyrin peroxidase enzyme models, with s = 5/2 and 3/2 Fe(III) quantum mixed spin (qms) ground states is described herein. The kinetic study by UV/Vis at ...

The reductive dissolution of Fe-oxide driven by organic matter oxidation is the primary mechanism accepted for As mobilization in several alluvial aquifers. These processes are often mediated by microorganisms that require a minimum Gibbs energy available to conduct the reaction in order to sustain their life functions. Implementing this threshold energy in reactive transport modeling is rarely...

Chemiluminescence has been used 10 study aerobic peroxidase-catalysed oxidation of indolyI-3-acetic acid (IAA). A threshold effect was found on inhibition of this reaction by its natural inhibitor caffeic acid. At an inhibitor concentration below threshold, only a temporary fall in the intensity of chemiluminescence and the reaction rale was established; at an above-threshold concentration, che...

The purified 15-lipoxygenase from rabbit reticulocytes is capable of oxidizing NADH in the presence of linoleic acid and oxygen. This co-oxidation proceeds at a rate that amounts to approx. 7% of linoleic acid oxygenation rates. Although NADH inhibits the lipoxygenase reaction with linoleic acid as substrate (46% inhibition at 0.2 mM NADH), the reaction specificity of the enzyme was not altered...

X-ray photoelectron and absorption spectroscopies (XPS and XAS) combined with on-line mass spectrometry were applied under working catalytic conditions to investigate the methanol oxidation on cobalt. Two cobalt oxidation states (Co3O4 and CoO) were prepared and investigated as regards their influence on the catalytic activity and selectivity. In addition adsorbed species were monitored in the ...

Wet oxidation of phenol, 2-chlorophenol, 4-chlorophenol and 2-nitrophenol over iron oxide and manganese dioxide catalysts was tested in this work with or without hydrogen peroxide in the reaction mixture. Influence of factors such as catalyst load, reactant-hydrogen peroxide mole ratio, and reaction time was monitored for all the phenols. Increase in the amount of hydrogen peroxide in the feed ...

The oxidation kinetics of phyllo(semi)quinone (PhQ), which acts as an electron transfer (ET) intermediate in the Photosystem I reaction centre, are described by a minimum of two exponential phases, characterised by lifetimes in the 10-30 ns and 150-300 ns ranges. The fastest phase is considered to be dominated by the oxidation of the PhQ molecule coordinated by the PsaB reaction centre subunit ...

In any artificial photosynthetic system, the oxidation of water to molecular oxygen provides the electrons needed for the reduction of protons or carbon dioxide to a fuel. Understanding how this four-electron reaction works in detail is important for the development of improved robust catalysts made of Earth-abundant materials, like first-row transition-metal oxides. Here, using time-resolved F...