Catalase-peroxidase haem (IPR000763)

Short name: Catalase_peroxidase

Overlapping homologous superfamilies

Family relationships



Haem-containing catalase-peroxidases are bifunctional antioxidant enzymes that exhibit both catalase (EC: and peroxidase (EC: activity, and which are present predominantly in bacterial species [PMID: 19129167]. Several evolutionary lineages are present also in archaeal, fungal, and protistan species. These enzymes provide protection against oxidative stress by dismutating hydrogen peroxide to oxygen and water [PMID: 18498226]. Phylogenetically they are closely related to ascorbate peroxidases and cytochrome c peroxidases [PMID: 1954228] and can be divided in two distinct clades [PMID: 20062977]. They do not share sequence similarity with mono-functional, haem-containing catalases (IPR002226) that are ubiquitous in aerobic organisms, nor with non-haem manganese-containing catalases found in bacteria (IPR007760). Catalases perform a unique two-step reaction cycle that cleaves two hydrogen peroxide molecules heterolytically to alternately oxidise and reduce the haem iron thus releasing water and molecular oxygen [PMID: 18498226]. Contrary, peroxidases use hydrogen peroxide only to oxidise the haem iron, but use different electron donors such as NADH or ascorbate to then reduce the haem.

The structure of the catalase-peroxidase from the archaeon, Haloarcula marismortui (Halobacterium marismortui), reveals a dimer of two identical subunits [PMID: 12172540], although some catalase-peroxidases can exist also as homotetramers. The general topology, as well as the arrangement of the catalytic residues and haem in the active site, are similar to other class I peroxidases. However, the location of the haem group deeply buried inside the domain is typical of a catalase. The primary structure of the subunit can be divided into two similar halves, which very probably arose from a gene duplication event [PMID: 1954228, PMID: 15291807]. A similar structure was obtained also for a catalase-peroxidase from the proteobacterium Burkholderia pseudomallei [PMID: 12628252].

GO terms

Biological Process

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

Molecular Function

GO:0004096 catalase activity
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.