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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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Journal Article
TL;DR: In this article, the reduction potentials of wine polyphenols and oxygen, as well as that of the Fe3+/Fe2+ couple, have been calculated for wine conditions and form the basis for discussing how these redox systems are likely to interact.
Abstract: The chemical, biochemical, and enological literature has been broadly surveyed to identify the reaction mechanisms of oxygen and of its intermediate reduction products that should apply to wine. The reduction potentials of redox couples derived from wine polyphenols and oxygen, as well as that of the Fe3+/Fe2+ couple, have been calculated for wine conditions and form the basis for discussing how these redox systems are likely to interact. Values obtained for wine quinone/catechol couples agree well with those reported for wine-model conditions. Catechol derivatives are oxidized sequentially to semiquinones and quinones, while oxygen is reduced in turn to hydroperoxyl radicals and hydrogen peroxide. The whole process is mediated by redox cycling of the Fe3+/Fe2+ couple, which is made possible by the lowering of its reduction potential by coordination of Fe3+ to hydroxy acids. Hydrogen peroxide is then further reduced by Fe2+ in the Fenton reaction to produce hydroxyl radicals, which oxidize saturated hydroxy compounds. Intermediate radicals may react with oxygen, providing an additional pathway for its reduction. Thus, both ferric and ferrous ions, which are present in wine, perform an important catalytic function. The antioxidant activity of bisulfite is largely restricted to its reaction with hydrogen peroxide. Direct reaction of sulfur dioxide with oxygen, which is a radical chain process, is prevented by the radical scavenging activity of polyphenols.

307 citations

Journal ArticleDOI
01 Jan 1993
TL;DR: An increase in free radical generation and a simultaneous decrease in the production of nitric oxide and anti-oxidants such as SOD and vitamin E occurs in essential hypertension, which can lead to an increase in peripheral vascular resistance and hypertension.
Abstract: Possible involvement of reactive oxygen species and nitric oxide in the pathogenesis of human essential hypertension was investigated. It was observed that both superoxide anion and hydrogen peroxide production by polymorphonuclear leukocytes and the plasma levels of lipid peroxides are higher in uncontrolled essential hypertension compared with normal controls. Nitric oxide levels measured as its stable metabolite nitrite, as an index of nitric oxide synthesis, revealed its levels to be low in hypertensive patients. Superoxide anion, hydrogen peroxide, lipid peroxides and nitric oxide levels reverted to normal values after the control of hypertension by drugs. The concentrations of anti-oxidants such as vitamin E and superoxide dismutase were found to be decreased in patients with uncontrolled hypertension. Several anti-hypertensive drugs inhibited lipid peroxidation in vitro. Angiotensin-II, a potent vasoconstrictor, stimulated free radical generation in normal leukocytes which could be blocked by calmo...

307 citations

Journal ArticleDOI
TL;DR: It is found that manganese does not protect peroxide‐stressed cells by scavenging peroxide, and the beneficial effects ofManganese correlate with its ability to metallate mononuclear enzymes, which may prevent protein damage.
Abstract: Very little manganese is imported into Escherichia coli under routine growth conditions: the import system is weakly expressed, the manganese content is low, and a manganese-dependent enzyme is not correctly metallated. Mutants that lack MntH, the importer, grow at wild-type rates, indicating that manganese plays no critical role. However, MntH supports the growth of iron-deficient cells, suggesting that manganese can substitute for iron in activating at least some metalloenzymes. MntH is also strongly induced when cells are stressed by hydrogen peroxide. This adaptation is essential, as E. coli cannot tolerate peroxide stress if mntH is deleted. Other workers have observed that manganese improves the ability of a variety of microbes to tolerate oxidative stress, and the prevailing hypothesis is that manganese does so by chemically scavenging hydrogen peroxide and/or superoxide. We found that manganese does not protect peroxide-stressed cells by scavenging peroxide. Instead, the beneficial effects of manganese correlate with its ability to metallate mononuclear enzymes. Because iron-loaded enzymes are vulnerable to the Fenton reaction, the substitution of manganese may prevent protein damage. Accordingly, during H2O2 stress, mutants that cannot import manganese and/or are unable to sequester iron suffer high rates of protein oxidation.

306 citations

Journal ArticleDOI
TL;DR: The use of S1QELs and S3 QELs, suppressors of mitochondrial O2̇̄/H2O2 generation that do not inhibit oxidative phosphorylation, are reviewed as tools to characterize the contributions of specific sites in situ and in vivo.

305 citations

Journal ArticleDOI
TL;DR: The automated methods are suitable for measuring glucose in serum, plasma from fluoride-or iodoacetate-preserved blood, urine (without ion-exchange pretreatment), or cerebrospinal fluid and eliminate the problem of falsely high results caused by medication or reducing metabolites associated with uremia.
Abstract: We describe an automated, colorimetric determination of glucose in biological fluids that combines the specificity of glucose oxidase and of a new peroxide indicator reaction. In the presence of peroxidase, 3-methyl-2-benzothiazolinone hydrazone oxidatively couples with N,N-dimethylaniline to form a stable, intensely colored, water-soluble indamine dye, the concentration of which is proportional to that of the third reactant, hydrogen peroxide. This reaction, used earlier to determine uric acid [Clin. Chem. 17, 1154 (1971)], is substantially less affected by negative interference of reducing substances than are previously described peroxide indicators. Results from use of AutoAnalyzers I and II and this method were compared with those from a manual spectrophotometric hexokinase/glucose-6-phosphate dehydrogenase procedure, and showed good correlation for specimens from patients. The automated methods are suitable for measuring glucose in serum, plasma from fluoride-or iodoacetate-preserved blood, urine (without ion-exchange pretreatment), or cerebrospinal fluid. They eliminate the problem of falsely high results caused by medication or reducing metabolites associated with uremia, in methods in which alkaline ferricyanide or copper—neocuproine is used.

303 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20242
20231,644
20223,392
2021897
20201,112
20191,301