CATH Classification

Domain Context

CATH Clusters

Superfamily Glutaredoxin
Functional Family Alkyl hydroperoxide reductase, peroxiredoxin

Enzyme Information

Carboxylic ester hydrolases.
based on mapping to UniProt P30041
Glutathione peroxidase.
based on mapping to UniProt P30041
2 glutathione + H(2)O(2) = glutathione disulfide + 2 H(2)O.
-!- Steroid and lipid hydroperoxides, but not the product of reaction of EC on phospholipids, can act as acceptor, but more slowly than H(2)O(2) (cf. EC
based on mapping to UniProt P30041
2 R'-SH + ROOH = R'-S-S-R' + H(2)O + ROH.
-!- 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. -!- The peroxidase reaction comprises two steps centered 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. -!- To recycle the disulfide, known atypical 2-Cys Prxs appear to use thioredoxin as an electron donor. -!- The 1-Cys Prxs conserve only the peroxidatic cysteine, so that its oxidized form is directly reduced to cysteine by the reductant molecule.

UniProtKB Entries (1)

Homo sapiens

PDB Structure

External Links
Primary Citation
Crystal structures of human peroxiredoxin 6 in different oxidation states
Kim, K.H., Lee, W.T., Kim, E.E.