Peroxidase


Peroxidase

Peroxidases (EC number [http://www.chem.qmul.ac.uk/iubmb/enzyme/EC1/11/1/ 1.11.1.x] ) are a large family of enzymes. A majority of peroxidase protein sequences can be found in the PeroxiBase database. Peroxidases typically catalyze a reaction of the form:

:ROOR' + electron donor (2 e-) + 2H+ → ROH + R'OH

For many of these enzymes the optimal substrate is hydrogen peroxide, but others are more active with organic hydroperoxides such as lipid peroxides. Peroxidases can contain a heme cofactor in their active sites, or redox-active cysteine or selenocysteine residues.

The nature of the electron donor is very dependent on the structure of the enzyme.
* For example, horseradish peroxidase can use a variety of organic compounds as electron donors and acceptors. Horseradish peroxidase has an accessible active site and many compounds can reach the site of the reaction.
* For an enzyme such as cytochrome c peroxidase, the compounds that donate electrons are very specific, because there is a very closed active site.

While the exact mechanisms have yet to be elucidated, peroxidases are known to play a part in increasing a plant's defenses against pathogens. [cite journal
author = Karthikeyan M et al
title = Induction of resistance in host against the infection of leaf blight pathogen (Alternaria palandui) in onion (Allium cepa var aggregatum).
journal = Indian J Biochem Biophys
volume = 42
issue = 6
pages = 371–7
date = 2005 Dec
pmid = 16955738
format =
] Peroxidases are sometimes used as histological marker. Cytochrome c peroxidase is used as a soluble, easily purified model for cytochrome c oxidase.

Glutathione peroxidase is a peroxidase found in humans, which contains selenocysteine. It uses glutathione as an electron donor and is active with both hydrogen peroxide and organic hydroperoxide substrates.

Amyloid beta, when bound to heme has been shown to have peroxidase activity. [cite journal
title = Amyloid-{beta} peptide binds with heme to form a peroxidase: Relationship to thecytopathologies of Alzheimer's disease | author = Hani Atamna, Kathleen Boyle | date = 21 Feb 2006 | journal = Proceedings of the National Academy of Science | volume = 103 | issue = 9 | pages = 3381 - 3386 | doi = 10.1073/pnas.0600134103
]

A typical group of peroxidases are the haloperoxidases. This group is able to form reactive halogen species and as a result natural organohalogen substances.

Applications

Peroxidase can be used for treatment of industrial waste waters. For example, phenols, which are important pollutants, can be removed by enzyme-catalyzed polymerization using horseradish peroxidase. Thus phenols are oxidized to phenoxy radicals which participate in reactions where are produced polymers and oligomers that are less toxic than phenols.

Furhermore, peroxidases can be an alternative option of a number of harsh chemicals, eliminating harsh reaction conditions. There are a lot of investigations about the use of peroxidase in many manufacturing processes like adhesives, computer chips, car parts, and linings of drums and cans.

ee also

* Haloperoxidase
* Myeloperoxidase (MPO)
* Catalase
* Hemoprotein
* Peroxide
* Peroxiredoxin
* Animal heme-dependent peroxidases
* Thyroid peroxidase

References


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Look at other dictionaries:

  • peroxidase — [pər äk′si dās΄] n. [ PER + OXIDASE] any oxidoreductase enzyme that acts as a catalyst in reactions in which a peroxide is reduced …   English World dictionary

  • Peroxidase — Peroxidasen Enzymklassifikation EC, Kategorie …   Deutsch Wikipedia

  • peroxidase — A haem enzyme that catalyses reduction of hydrogen peroxide by a substrate that loses two hydrogen atoms. Within cells, may be localized in peroxisomes. Coloured reaction products allow detection of the enzyme with high sensitivity, so peroxidase …   Dictionary of molecular biology

  • peroxidase — peroksidazė statusas T sritis chemija apibrėžtis Fermentas, katalizuojantis peroksidų redukciją. atitikmenys: angl. peroxidase rus. пероксидаза …   Chemijos terminų aiškinamasis žodynas

  • peroxidase — noun Date: 1900 an enzyme that catalyzes the oxidation of various substances by peroxides …   New Collegiate Dictionary

  • peroxidase — /peuh rok si days , dayz /, n. Biochem. any of a class of oxidoreductase enzymes that catalyze the oxidation of a compound by the decomposition of hydrogen peroxide or an organic peroxide. [1900 05; PEROXIDE + ASE] * * * …   Universalium

  • peroxidase — noun Any of a class of enzymes that act on substrates such as hydrogen peroxide and organic hydroperoxides such as lipid peroxides …   Wiktionary

  • Peroxidase — Per|oxi|da|se 〈f. 19; Biochem.〉 Peroxid spaltendes Enzym * * * Per|o|xi|da|se [↑ Peroxid u. ↑ ase], die; , n: Gruppenbez. für in Pflanzen u. bes. in Peroxisomen häufig anzutreffende Häm Eisen Proteine, die als Oxidoreduktasen die Oxidation… …   Universal-Lexikon

  • peroxidase — per·ox·i·dase pə räk sə .dās, .dāz n an enzyme occurring esp. in plants, milk, and white blood cells and consisting of a protein complex with hematin groups that catalyzes the oxidation of various substances by peroxides * * * n. an enzyme, found …   Medical dictionary

  • Peroxidase — Per|o|xi|da|se 〈f.; Gen.: , Pl.: n; Biochemie〉 Peroxid spaltendes Enzym …   Lexikalische Deutsches Wörterbuch


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