Hydrogen peroxide, detoxification

Those Dps proteins that bind DNA do so nonspecifically via positive residues at the N-terminus of the protein. When a cell is under prolonged stress. Dps cocrystallizes with DNA in vivo. This process is favored because it occurs spontaneously and does not deplete the cell s ATP levels. The formation of a multilayered complex provides a physical barrier around the DNA in addition to the hydrogen peroxide detoxification that accompanies iron oxidation. ... 

Halbach S, Baliatori N and Clarkson TW (1988) Mercury vapor uptake and hydrogen peroxide detoxification in human and mouse red blood cells. Toxicol Appl Pharmacol 96 517-524... 

Rosmarinic acid fulfils the requiremenis for being considered as a potent antioxidant since it is not only capable of efficiently scavenging superoxide anions, but is also able to chelate iron ions. Studies on other possible mechanisms for rosmarinic acid acting as an antioxidant, such as hydrogen peroxide detoxification through peroxidase-catalyxed reactions (5), are now in progress. In the search for sources of this compound, lavandin cell cultures must be considered since (hey accumulate relatively high amounts of easy-io-purify rosmarinic acid. 

Zhao GH, Ceci P, Ilari A, Giangiacomo L, Laue TM, Chiancone E, Chasteen ND. 2002. Iron and hydrogen peroxide detoxification properties of DNA-binding protein from starved cells a fertitm-hke DNA-binding protein of Escherichia coli. J Biol Chem 277 27689-27696. 

Zhao GH, Arosio P, Chasteen ND. 2006. Iron(II) and hydrogen peroxide detoxification by human H-chain ferritin an EPR spin-trapping study. Biochemistry 45 3429-3436. 

The GSH reductase inhibitor l,3-bis(2-chloroethyl)-l-nitrosourea (BCNU) also promotes corneal swelling in the isolated cornea. The addition of GSH prevents the action of BCNU as the cornea needs a constant supply of NADPH for maintaining adequate concentrations of reduced glutathione for the detoxification of hydrogen peroxide. It has been shown that hydrogen peroxide and BCNU primarily affect the permeability of the endothelial cells rather than the active processes transporting sodium and chloride ions across the membrane (Riley, 1985). 

Gaseous detoxification systems, based on hydrogen peroxide, 14 64-65 Gaseous effluents... 

Liquid/gaseous detoxification systems, based on hydrogen peroxide, 14 64-65 Liquid-gas separator system, in sulfonation systems, 23 552 Liquid halogen fluorides, 13 128 Liquid heat-transfer media, 12 83 Liquid helium... 

In order to relate structure and function at a more direct level, it is necessary to focus on systems which have better characterized structure than the complex membrane bound proteins like cyt c oxidase. One particularly useful paradigm in this context is the cytochrome c-cytochrome c peroxidase couple [18]. Cep is not involved in electron transport, per se its apparent function [19] is detoxification of hydrogen peroxide via the sequence H2O2 -I- cep Fe(III) -> H2O -I- cep Fe(IV) O (protein) compound ES ... 

Catalase [12] Bovine liver 2H2O2 —> 2H2O + O2 Detoxification of hydrogen peroxide... 

The polymerization of phenols or aromatic amines is applied in resin manufacture and the removal of phenols from waste water. Polymers produced by HRP-catalyzed coupling of phenols in non-aqueous media are potential substitutes for phenol-formaldehyde resins [123,124], and the polymerized aromatic amines find applications as conductive polymers [112]. Phenols and their resins are pollutants in aqueous effluents derived from coal conversion, paper-making, production of semiconductor chips, and the manufacture of resins and plastics. Their transformation by peroxidase and hydrogen peroxide constitutes a convenient, mild and environmentally acceptable detoxification process [125-127]. 

Bagchi and Kleiner suggested that endogenous HA can undergo dismutation by the action of a cyanobacterial hydroxylamine dismutase, thereby providing a detoxification mechanism for excess hydrogen peroxide, as well as for an excess of HA itself. This... 

The presence of benzo[6]thiophene in commercial naphthalene, its possible contamination with isomeric thienothiophenes 1 and 2, and their ability to poison aromatic hydrogenation catalysts led Maxted and Walker to develop detoxification by a preliminary short hydrogenation, in which thienothiophenes 1 and 2, and benzo[6]-thiophene are adsorbed on the catalyst. This is followed by their hydrogenation products that can easUy be oxidized with hydrogen peroxide or permolybdic acid to nontoxic sulfones subsequent hydrogenation of the aromatic hydrocarbons is then performed as usual. 

In 1948 Maxted and Walker studied the detoxification of catalyst poisons in the hydrogenation of aromatic hydrocarbons and found that the isomeric thienothiophenes 1 and 2 could be converted into the sul-fones of fully hydrogenated thienothiophenes 1 and 2, which do not poison the catalysts. This conversion is performed by brief preliminary hydrogenation and subsequent oxidation by hydrogen peroxide or per-molybdic acid. However, no data on the isolation or foe properties of these disulfones are available. It has been reported that direct oxidation of thienothiophenes 1 and 2 does not produce sulfones. 

Environmental applications require detoxification of hazardous substances to a level of parts per million (ppm) and even parts per billion (ppb). These purity levels, which were rarely considered in product synthesis, are now possible for wastewater due to Fenton s reagent. Fenton s oxidant is cost effective and relatively fast in destroying many toxics (Bigda, 1996). It attacks all reactive substrate concentrations under acidic conditions. Hydrogen peroxide is used to remove such contaminants as cyanide, sulfides, sulfites, chrome, and heavy metals by varying batch conditions. With an iron catalyst, the process often oxidizes organics, as well as reducing hexavalent chrome to trivalent precipitable form. 

If fatty acid catabolism by peroxisomes is increased by DEHP exposure and excess hydrogen peroxide is produced, there is an increased requirement for detoxification by peroxisomal catalase and the cellular peroxidases. However, the data concerning the impact of DEHP on catalase in rats are inconsistent. 

Wagner M, Nicell JA. Detoxification of phenolic solutions with horseradish peroxidase and hydrogen peroxide. Wat Res 2002 36(16) 4041-4052. 

Oxidation in acidic solution can be achieved by Caro s acid, for example at 85 °C.247 This chemistry is employed in the extraction of chromium from superalloy scrap.248 It can also be used to detoxify, recover or re-cycle effluents from chromic acid oxidation or pickling liquors. Detoxification and recovery of chromic acid solutions is by the addition of hydrogen peroxide which reduces the chromium(III) salts, followed by alkali to precipitate and separate chromium hydroxide.249 Re-cycle can be by direct re-oxidation with Caro s acid, or by first raising the pH to alkaline levels, oxidation with hydrogen peroxide and re-acidification with subsequent salt by-product production. 

When intermediate-sized additions are made (100-500 Fe per molecule), some of the hydrogen peroxide produced in reaction (4) is used to oxidize ferrous iron in a hydrogen peroxide/iron detoxification reaction (equation 6) ... 

Superoxide Reductase (see Iron Proteins with Mononuclear Active Sites). Detoxification of reactive oxygen species in anaerobic microorganisms has recently been shown to center around SOR, a novel mononuclear iron enzyme that reduces superoxide to hydrogen peroxide (see equation 4), rather than dismuting superoxide to oxygen and hydrogen peroxide as is the case for the superoxide dismutases found in aerobic organisms. 

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