Oxidation of Thiol Groups by Catalase.

Pathways of peroxynitrite oxidation of thiol groups.

Peroxynitrite mediates the oxidation of the thiol group of both cysteine and glutathione. This process is associated with oxygen consumption. At acidic pH and a cysteine/peroxynitrite molar ratio of < or = 1.2, there was a single fast phase of oxygen consumption, which increased with increasing concentrations of both cysteine and oxygen. At higher molar ratios the profile of oxygen consumption ...

Ascorbic acid oxidation of thiol groups from dithiotreitol is mediated by its conversion to dehydroascorbic acid

The aim of the present study was to investigate whether the in vitro pro-oxidant effect of ascorbic acid towards thiol groups could be mediated by free radicals formed during its auto-oxidation and/or by a direct oxidation of -SH groups by its oxidized form (dehydroascorbic acid). This hypothesis was examined by measuring the rate of AA (ascorbic acid) oxidation in MOPS (3-morpholinepropanesulf...

The oxidation of protein thiol groups by iodate, bromate and persulphate.

Oxidation of thiol compounds by catalase and peroxidase in the presence of manganese(II) and phenols [proceedings].

complex reacted rapidly with 02-. in a catalytic manner. The rate constant for O,-* dismutation was determined by competition of the iron porphyrin with Nitro Blue Tetrazolium in a xanthine/xanthine oxidase system at pH 10.1 ; a value of 3 x ~O'M-' .s-' at 20°C was obtained. The iron porphyrin had no effect on xanthine oxidase activity. Under our reaction conditions, at least 14 molecules of Oz...

Stereospecificity of the oxidation of ethanol by catalase.

The primary action of catalase, the ability to decompose hydrogen peroxide with the evolution of osygen, was originally described by Thbnoud in 1911 (1). Keilin and Hartrcc (2) later showed that catalase was also capable of oxidizing a wide variety of compounds including ethanol in the presence of a hydrogen peroxide-generating system. The present study was undertaken to determine the stereospe...