The Enzyme Database

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EC 1.11.1.15     
Accepted name: peroxiredoxin
Reaction: 2 R′-SH + ROOH = R′-S-S-R′ + H2O + ROH
For diagram of reaction, click here and for mechanism, click here
Other name(s): thioredoxin peroxidase; tryparedoxin peroxidase; alkyl hydroperoxide reductase C22; AhpC; TrxPx; TXNPx; Prx; PRDX
Systematic name: thiol-containing-reductant:hydroperoxide oxidoreductase
Comments: Peroxiredoxins (Prxs) are a ubiquitous family of antioxidant proteins. They can be divided into three classes: typical 2-Cys, atypical 2-Cys and 1-Cys peroxiredoxins [1]. The peroxidase reaction comprises two steps centred around a redox-active cysteine called the peroxidatic cysteine. All three peroxiredoxin classes have the first step in common, in which the peroxidatic cysteine attacks the peroxide substrate and is oxidized to S-hydroxycysteine (a sulfenic acid) (see mechanism). The second step of the peroxidase reaction, the regeneration of cysteine from S-hydroxycysteine, distinguishes the three peroxiredoxin classes. For typical 2-Cys Prxs, in the second step, the peroxidatic S-hydroxycysteine from one subunit is attacked by the ’resolving’ cysteine located in the C-terminus of the second subunit, to form an intersubunit disulfide bond, which is then reduced by one of several cell-specific thiol-containing reductants (R′-SH) (e.g. thioredoxin, AhpF, tryparedoxin or AhpD), completing the catalytic cycle. In the atypical 2-Cys Prxs, both the peroxidatic cysteine and its resolving cysteine are in the same polypeptide, so their reaction forms an intrachain disulfide bond [1]. To recycle the disulfide, known atypical 2-Cys Prxs appear to use thioredoxin as an electron donor [3]. The 1-Cys Prxs conserve only the peroxidatic cysteine, so that its oxidized form is directly reduced to cysteine by the reductant molecule [4].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, UM-BBD, CAS registry number: 207137-51-7
References:
1.  Wood, Z.A., Schröder, E., Harris, J.R. and Poole, L.B. Structure, mechanism and regulation of peroxiredoxins. Trends Biochem. Sci. 28 (2003) 32–40. [PMID: 12517450]
2.  Hofmann, B., Hecht, H.J. and Flohé, L. Peroxiredoxins. Biol. Chem. 383 (2002) 347–364. [PMID: 12033427]
3.  Seo, M.S., Kang, S.W., Kim, K., Baines, I.C., Lee, T.H. and Rhee, S.G. Identification of a new type of mammalian peroxiredoxin that forms an intramolecular disulfide as a reaction intermediate. J. Biol. Chem. 275 (2000) 20346–20354. [PMID: 10751410]
4.  Choi, H.J., Kang, S.W., Yang, C.H., Rhee, S.G. and Ryu, S.E. Crystal structure of a novel human peroxidase enzyme at 2.0 Å resolution. Nat. Struct. Biol. 5 (1998) 400–406. [PMID: 9587003]
[EC 1.11.1.15 created 2004]
 
 


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