منابع مشابه
Myeloperoxidase oxidation states involved in myeloperoxidase-oxidase oxidation of thiols.
The changes in the oxidation state of the leucocyte enzyme myeloperoxidase, induced by buffer and thiols, were studied with visible-light-absorption spectroscopy. It was concluded that phosphate buffer contains small amounts of H2O2 and that thiols, when added to buffer, induce the generation of minute amounts of superoxide radical anion. These minute amounts of reduced oxygen species are sugge...
متن کاملSuperoxide-dependent oxidation of melatonin by myeloperoxidase.
Myeloperoxidase uses hydrogen peroxide to oxidize numerous substrates to hypohalous acids or reactive free radicals. Here we show that neutrophils oxidize melatonin to N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) in a reaction that is catalyzed by myeloperoxidase. Production of AFMK was highly dependent on superoxide but not hydrogen peroxide. It did not require hypochlorous acid, singlet...
متن کاملAntioxidant Effects of Vitamins C and E on the Low-Density Lipoprotein Oxidation Mediated by Myeloperoxidase
Background: Oxidative modification of low-density lipoprotein (LDL) appears to be an early step in the pathogenesis of atherosclerosis. Meanwhile, myeloperoxidase (MPO)-catalyzed reaction is one of the potent pathway for LDL oxidation in vivo. The aim of this study was to evaluate in vitro antioxidant effects of vitamins C and E on LDL oxidation mediated by MPO. Methods: MPO was isolated from f...
متن کاملMyeloperoxidase-catalyzed oxidation of melatonin by activated neutrophils.
In the presence of hydrogen peroxide, horseradish peroxidase (HRP) catalyzes the production of N(1)-acetyl-N(2)-formyl-5-methoxykynuramine from melatonin. This reaction consumes oxygen and exhibits chemiluminescence in the 440-540 nm region. The excited cleavage product derived from the thermolysis of an intermediate dioxetane is suggested to be the emitting species. Chemiluminescence and the i...
متن کاملOxidation of the flavonol quercetin by polyphenol oxidase.
Because direct oxidation of flavonols by polyphenol oxidase (PPO) has not previously been reported and, given the importance of flavonols, the ability of broad bean seed PPO to oxidize the flavonol quercetin was studied. The reaction was followed by recording spectral changes with time. Maximal spectral changes were observed at 291 nm (increase) and at 372 nm (decrease). The presence of two iso...
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ژورنال
عنوان ژورنال: Research Letters in Physical Chemistry
سال: 2009
ISSN: 1687-6873,1687-6881
DOI: 10.1155/2009/614362