EC - Peroxiredoxin

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IntEnz Enzyme Nomenclature


Accepted name:
Other names:
alkyl hydroperoxide reductase C22
thioredoxin peroxidase
tryparedoxin peroxidase
Systematic name:
thiol-containing-reductant:hydroperoxide oxidoreductase



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). 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

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0051920
UniProtKB/Swiss-Prot: (338) [show] [UniProt]


  1. Wood, Z.A., Schröder, E., Harris, J.R. and Poole, L.B.
    Structure, mechanism and regulation of peroxiredoxins.
    Trends Biochem. Sci. 28: 32-40 (2003).
  2. Hofmann, B., Hecht, H J. and Flohé, L.
    Biol. Chem. 383: 347-364 (2002). [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: 20346-20354 (2000). [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: 400-406 (1998). [PMID: 9587003]

[EC created 2004]