EC - NADH-dependent peroxiredoxin

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IntEnz Enzyme Nomenclature


Accepted name:
NADH-dependent peroxiredoxin
Other name:
alkyl hydroperoxide reductase
Systematic name:
NADH: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 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. The 1-Cys Prxs conserve only the peroxidatic cysteine, so its regeneration involves direct interaction with a reductant molecule. This bacterial peroxiredoxin differs from most other forms by comprising two types of subunits. One subunit (AhpC) is a typical 2-Cys peroxiredoxin. Following the reduction of the substrate, one AhpC subunit forms a disulfide bond with an identical unit. The disulfide bond is reduced by the second type of subunit (AhpF). This second subunit is a flavin-containing protein that uses electrons from NADH to reduce the cysteine residues on the AhpC subunits back to their active state. Formerly EC

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0102039
UniProtKB/Swiss-Prot: (31) [show] [UniProt]


  1. Wood, Z. A., Schroder, E., Robin Harris, J., Poole, L. B.
    Structure, mechanism and regulation of peroxiredoxins.
    Trends Biochem. Sci. 28 : 32-40 (2003). [PMID: 12517450]
  2. Dip, P. V., Kamariah, N., Subramanian Manimekalai, M. S., Nartey, W., Balakrishna, A. M., Eisenhaber, F., Eisenhaber, B., Gruber, G.
    Structure, mechanism and ensemble formation of the alkylhydroperoxide reductase subunits AhpC and AhpF from Escherichia coli.
    Acta Crystallogr. D Biol. Crystallogr. 70 : 2848-2862 (2014). [PMID: 25372677]
  3. Nartey, W., Basak, S., Kamariah, N., Manimekalai, M. S., Robson, S., Wagner, G., Eisenhaber, B., Eisenhaber, F., Gruber, G.
    NMR studies reveal a novel grab and release mechanism for efficient catalysis of the bacterial 2-Cys peroxiredoxin machinery.
    FEBS J. 282 : 4620-4638 (2015). [PMID: 26402142]

[EC created 1983 as EC, part transferred 2020 to EC]