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'''Chloride peroxidase''' ({{EC number|1.11.1.10}}) is a family of [[enzyme]]s that catalyzs the [[halogenation|chlorination]] of organic compounds. This enzyme combines the inorganic substrates [[chloride]] and [[hydrogen peroxide]] to produce the equivalent of Cl<sup>+</sup>, which replaces a proton in hydrocarbon substrate: |
'''Chloride peroxidase''' ({{EC number|1.11.1.10}}) is a family of [[enzyme]]s that catalyzs the [[halogenation|chlorination]] of organic compounds. This enzyme combines the inorganic substrates [[chloride]] and [[hydrogen peroxide]] to produce the equivalent of Cl<sup>+</sup>, which replaces a proton in hydrocarbon substrate: |
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:R-H + Cl<sup>-</sup> + H<sub>2</sub>O<sub>2</sub> + H<sup>+</sup> → R-Cl + 2 H<sub>2</sub>O |
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Many organochlorine compounds are [[biosynthesis|biosynthesized]] in this way. |
Many organochlorine compounds are [[biosynthesis|biosynthesized]] in this way. |
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This enzyme belongs to the family of [[oxidoreductase]]s, specifically those acting on a peroxide as acceptor (peroxidases). The systematic name of this enzyme class is '''chloride:hydrogen-peroxide oxidoreductase'''. This enzyme is also called '''chloroperoxidase'''. It employs one [[cofactor (biochemistry)|cofactor]] which may be either [[heme]] or vanadium. |
This enzyme belongs to the family of [[oxidoreductase]]s, specifically those acting on a peroxide as acceptor (peroxidases). The systematic name of this enzyme class is '''chloride:hydrogen-peroxide oxidoreductase'''. This enzyme is also called '''chloroperoxidase'''. It employs one [[cofactor (biochemistry)|cofactor]] which may be either [[heme]] or vanadium.<ref>{{Cite journal|journal = Natural Product Reports|year = 2004|volume = 21|issue = 1|pmid = 15039842|doi = 10.1039/b302337k|title = The role of vanadium bromoperoxidase in the biosynthesis of halogenated marine natural products|first = Alison|last = Butler|coauthors = Carter-Franklin, Jayme N.|pages = 180–8}} (this paper also discussed chloroperoxidases.</ref> |
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The heme-containing chloroperoxidase (CPO) exhibits peroxidase, [[catalase]] and [[cytochrome P450]]-like activities in addition to catalyzing halogenation reactions.<ref name="PUB00005255">{{cite journal |doi=10.1016/S0969-2126(01)00274-X |author=Poulos TL, Sundaramoorthy M, Terner J |title=The crystal structure of chloroperoxidase: a heme peroxidase--cytochrome P450 functional hybrid |journal=Structure |volume=3 |issue=12 |pages=1367–1377 |year=1995 |pmid=8747463}}</ref> Despite functional similarities with other heme enzymes, the structure of CPO is unique, which folds into a tertiary structure dominated by eight helical segments. The catalytic acid base, required to cleave the peroxide O-O bond, is glutamic acid rather than histidine as in [[horseradish peroxidase]]. |
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==Structural studies== |
==Structural studies== |
Revision as of 00:48, 16 September 2013
Chloride peroxidase (EC 1.11.1.10) is a family of enzymes that catalyzs the chlorination of organic compounds. This enzyme combines the inorganic substrates chloride and hydrogen peroxide to produce the equivalent of Cl+, which replaces a proton in hydrocarbon substrate:
- R-H + Cl- + H2O2 + H+ → R-Cl + 2 H2O
Many organochlorine compounds are biosynthesized in this way.
This enzyme belongs to the family of oxidoreductases, specifically those acting on a peroxide as acceptor (peroxidases). The systematic name of this enzyme class is chloride:hydrogen-peroxide oxidoreductase. This enzyme is also called chloroperoxidase. It employs one cofactor which may be either heme or vanadium.[1]
The heme-containing chloroperoxidase (CPO) exhibits peroxidase, catalase and cytochrome P450-like activities in addition to catalyzing halogenation reactions.[2] Despite functional similarities with other heme enzymes, the structure of CPO is unique, which folds into a tertiary structure dominated by eight helical segments. The catalytic acid base, required to cleave the peroxide O-O bond, is glutamic acid rather than histidine as in horseradish peroxidase.
Structural studies
As of late 2007, 30 structures have been solved for this class of enzymes, with PDB accession codes 1A7U, 1A88, 1A8Q, 1A8S, 1A8U, 1BRT, 1CPO, 1IDQ, 1IDU, 1QHB, 1QI9, 1VNC, 1VNE, 1VNF, 1VNG, 1VNH, 1VNI, 1VNS, 2CIV, 2CIW, 2CIX, 2CIY, 2CIZ, 2CJ0, 2CJ1, 2CJ2, 2CPO, 2J18, 2J19, and 2J5M.
References
- ^ Butler, Alison (2004). "The role of vanadium bromoperoxidase in the biosynthesis of halogenated marine natural products". Natural Product Reports. 21 (1): 180–8. doi:10.1039/b302337k. PMID 15039842.
{{cite journal}}
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ignored (|author=
suggested) (help) (this paper also discussed chloroperoxidases. - ^ Poulos TL, Sundaramoorthy M, Terner J (1995). "The crystal structure of chloroperoxidase: a heme peroxidase--cytochrome P450 functional hybrid". Structure. 3 (12): 1367–1377. doi:10.1016/S0969-2126(01)00274-X. PMID 8747463.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)
Other reading
- Hager LP, Hollenberg PF, Rand-Meir T, Chiang R, Doubek D (1975). "Chemistry of peroxidase intermediates". Ann. N. Y. Acad. Sci. 244: 80–93. doi:10.1111/j.1749-6632.1975.tb41524.x. PMID 1056179.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Morris DR, Hager LP (1966). "Chloroperoxidase. I. Isolation and properties of the crystalline glycoprotein". J. Biol. Chem. 241 (8): 1763–8. PMID 5949836.
- Theiler R, Cook JC, Hager LP and Siuda JF (1978). "Halohydrocarbon synthesis by homoperoxidase". Science. 202 (4372): 1094–1096. doi:10.1126/science.202.4372.1094. PMID 17777960.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)