Plant peroxidase (IPR000823)

Short name: Peroxidase_pln

Family relationships


Peroxidases are haem-containing enzymes that use hydrogen peroxide as the electron acceptor to catalyse a number of oxidative reactions. Most haem peroxidases follow the reaction scheme:

Fe3+ + H2O2 --> [Fe4+=O]R' (Compound I) + H2O [Fe4+=O]R' + substrate --> [Fe4+=O]R (Compound II) + oxidised substrate [Fe4+=O]R + substrate --> Fe3+ + H2O + oxidised substrate

In this mechanism, the enzyme reacts with one equivalent of H2O2 to give [Fe4+=O]R' (compound I). This is a two-electron oxidation/reduction reaction where H2O2 is reduced to water and the enzyme is oxidised. One oxidising equivalent resides on iron, giving the oxyferryl [PMID: 8062820] intermediate, while in many peroxidases the porphyrin (R) is oxidised to the porphyrin pi-cation radical (R'). Compound I then oxidises an organic substrate to give a substrate radical [PMID: 7922023].

Peroxidases are found in bacteria, fungi, plants and animals and can be viewed as members of a superfamily consisting of 3 major classes. Class III comprises the secretory plant peroxidases, which have multiple tissue-specific functions e.g., removal of hydrogen peroxide from chloroplasts and cytosol; oxidation of toxic compounds; biosynthesis of the cell wall; defence responses towards wounding; indole-3-acetic acid (IAA) catabolism; ethylene biosynthesis; and so on. The wide spectrum of peroxidase activity, coupled with the participation in various physiological processes, is in keeping with its relative lack of specificity for substrates and the occurrence of a variety of isozymes. Plant peroxidases are monomeric glycoproteins containing 4 conserved disulphide bridges and 2 calcium ions. The 3D structure of peanut peroxidase has been shown to possess the same helical fold as class I and II peroxidases [PMID: 8805539].

GO terms

Biological Process

GO:0055114 oxidation-reduction process
GO:0006979 response to oxidative stress

Molecular Function

GO:0020037 heme binding
GO:0004601 peroxidase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.