Homologous Superfamily

Haem peroxidase (IPR010255)

Short name: Haem_peroxidase


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].

Haem peroxidases include two superfamilies: one found in bacteria, fungi, plants and the second found in animals. The animal peroxidases comprise a group of homologous proteins that differ markedly from the plant/fungal/bacterial peroxidases in primary, secondary and tertiary structure, but which share with them a common function. Animal peroxidases probably arose independently of the plant/fungal/bacterial peroxidase superfamily and most likely belong to a different gene family. The crystal structures of a number of these proteins show that the active sites of animal peroxidase and plant/fungal/bacterial peroxidases are remarkably similar [PMID: 10403190].

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.