Topic
Hydrogen peroxide
About: Hydrogen peroxide is a research topic. Over the lifetime, 42583 publications have been published within this topic receiving 1043732 citations. The topic is also known as: H2O2 & dioxidane.
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TL;DR: It is concluded that the species observed is the superoxide ion, O(2) (-), and that the stability of this ion is greatly increased in alkaline solution.
Abstract: 1. An electron-spin-resonance signal with g( parallel)2.08 and g( perpendicular)2.00 is observed by the rapid-freezing technique during the oxidation of substrates by molecular oxygen catalysed by xanthine oxidase at pH10. 2. The intensity of this signal is shown to depend on oxygen rather than on enzyme concentration, indicating that it is due to an oxygen free radical and not to the enzyme. 3. The same species is shown to be produced in the reaction at pH10 between hydrogen peroxide and periodate ions. Studies with this system have facilitated comparison of the properties of the oxygen radical with data in the literature on the products of pulse radiolysis of oxygenated water over a wide pH range. 4. It is concluded that the species observed is the superoxide ion, O(2) (-), and that the stability of this ion is greatly increased in alkaline solution. A mechanism explaining the alkaline stability is proposed. 5. The importance of O(2) (-) in the enzymic reaction is discussed.
220 citations
TL;DR: In this article, the results showed that the active carbon is essentially amorphous and indicated the presence of traces of oxides of calcium and magnesium, while infrared spectroscopy showed peaks relating to hydroxyl, aliphatic, ether, aromatic and phenolic groups.
220 citations
TL;DR: The initial oxidation reaction was found to fit into first order rate kinetics and the rate of oxidation of H-acid was higher than the other dyes, indicating that the dye degradation proceeds through cleavage of the substituent group.
219 citations
TL;DR: It is proposed that the peroxidase/phenolics/AA system can function as a hydrogen peroxide scavenging system and that in addition to AA, MDA radicals may also reduce phenoxyl radicals.
Abstract: The function of a peroxidase/phenolics/ascorbic acid system in plant vacuoles has not yet been well elucidated. We wished to study the redox reactions among hydrogen peroxide, phenolics and ascorbic acid (AA) in the presence of horseradish peroxidase. Horseradish peroxidase oxidized rutin and chlorogenic acid (CGA), compounds present in many kinds of plant. The oxidation was inhibited by AA. As a result of the inhibition, AA was oxidized and when almost all of it had been oxidized, oxidation of the phenolics commenced. Monodehydroascorbic acid (MDA) radical was detected during the oxidation of AA, suggesting that the inhibition of oxidation of rutin and CGA was due to reduction of phenoxyl radicals by AA. By comparison of time courses of changes in levels of AA and MDA radicals, and by kinetic calculation, it is suggested that in addition to AA, MDA radicals may also reduce phenoxyl radicals. It is proposed that the peroxidase/phenolics/AA system can function as a hydrogen peroxide scavenging system.
219 citations
TL;DR: Data indicate that oxidation of ascorbic acid by hydrogen peroxide primarily proceeds through three major six-carbon intermediates, each with distinctive redox properties, which indicate that the stable metabolite diketogulonic may be a critical antioxidant in asCorbic-acid-containing systems.
219 citations