This MedLibrary.org supplementary page on Peroxidase is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
Peroxidases (EC number 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.1 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.2
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.
See also
- Haloperoxidase
- Myeloperoxidase (MPO)
- Catalase
- Hemoprotein
- Peroxide
- Peroxiredoxin
- Animal heme-dependent peroxidases
- Thyroid peroxidase
- Vanadium bromoperoxidase
References
- ^ Karthikeyan M et al (December 2005). "Induction of resistance in host against the infection of leaf blight pathogen (Alternaria palandui) in onion (Allium cepa var aggregatum).". Indian J Biochem Biophys 42 (6): 371–7. PMID 16955738.
- ^ Hani Atamna, Kathleen Boyle (21 Feb 2006). "Amyloid-{beta} peptide binds with heme to form a peroxidase: Relationship to the cytopathologies of Alzheimer's disease". Proceedings of the National Academy of Science 103 (9): 3381 - 3386. doi:.
|
||||||||
|
|||||
Wikipedia content modification information:
- This page was last modified on 26 November 2008, at 09:18.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Peroxidase".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.