Main Page | See live article | Alphabetical index A peroxidase is an enzyme, usually containing heme, that catalyzes a reaction of the form: ROOR' + electron donor (2 e-) + 2H+ → ROH + R'OH Many of these compounds are optimally designed to process hydrogen peroxide. The nature of the electron donor is very dependent on the specific nature of the enzyme itself. For a compound such as horseradish peroxidase, the number of organic compounds it can use as electron donors is substantial. Horseradish peroxidase has a broad and accessible active site and many compounds can reach the site of the reaction. For a compound such as cytochrome c peroxidase, the compounds that donate electrons are very specific, because there is a very closed active site. Peroxidases are sometimes used as histological markers. Cytochrome c peroxidase is used as a soluble, easily purified model for cytochrome c oxidase. Glutathione peroxidase is a peroxidase found in humans containing selenocysteine. see also: peroxide, catalase, hemoprotein This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.