Hydrogen peroxide enzyme-catalyzed oxidation

In blood or tissues, this reaction is catalyzed by an enzyme called catalase (Figure 11.13). When 3% hydrogen peroxide is used to treat a fresh cut or wound, oxygen gas is given off rapidly. The function of catalase in the body is to prevent the build-up of hydrogen peroxide, a powerful oxidizing agent. 

More than 90% of commercially available enzyme-based biosensors and analytical kits contain oxidases as terminal enzymes responsible for generation of analytical signal. These enzymes catalyze oxidation of specific analyte with molecular oxygen producing hydrogen peroxide according to the reaction ... 

It is well known that most of the antioxidant enzymes and substrates can exhibit prooxidant activity under certain conditions, mainly because many stages of the reactions catalyzed by such enzymes are reversible. The question of possible prooxidant effects of SODs and the ability of SODs to react with the other substrates than superoxide have been studied for a long time. It is known that CuZnSOD is inactivated by the hydrogen peroxide formed. Hodgson and Fridovich [3] proposed that this inactivation depends on the reaction of hydrogen peroxide with the oxidized form Cu(II)ZnSOD yielding the bound hydroxyl radicals. 

The bombardier beetle defends itself by spraying a hot quinone solution from its abdomen (see photo). This solution is formed by the enzyme-catalyzed oxidation of hydroquinone by hydrogen peroxide. Write a balanced equation for this oxidation. 

Peroxidase and catalase enzymes catalyze oxidations by hydrogen peroxide and the disproportionation of hydrogen peroxide into dioxygen and water (equations 36 and 37). The two classes of... 

Hydrogen peroxide (H2O2) is one of the most important products or substrate of enzyme catalyzed oxidation reactions. Most common enzymes used in biosensors are oxidases, which catalyze the model oxidation reactions ... 

Glutathione Peroxidase An enzyme catalyzing the oxidation of 2 moles of glutathione in the presence of hydrogen peroxide to yield oxidized glutathione and water. EC 1.11.1.9. [NIH]... 

The reaction was catalyzed by a complex of iron with -ethylene bis(sallicylidene amine) as well as a horseradish peroxidase enzyme to carry out oxidative coupling of phenols using hydrogen peroxide as an oxidizing agent. The product is a new type of plastic. 

As the electrode moves closer to the cell surface, the amperometric current rises (Figure 17.1.3C). When the electrode is placed in contact with the cell surface, cholesterol is extracted from the membrane and moves across the thin membrane layer and partitions into the electrode-supported enzyme-modified lipid bilayer. Subsequent enzyme catalyzed oxidation of cholesterol by molecular oxygen produces hydrogen peroxide which is oxidized at the platinum electrode and detected. This is an efficient and simple method to determine cholesterol levels in the plasma membrane of cells which should find applicability in determining the role cholesterol plays in the organization of cellular membranes (51). 

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