Catalase, clade 3 (IPR040333)

Short name: Catalase_3

Overlapping homologous superfamilies

Family relationships


Catalases (EC: are antioxidant enzymes that catalyse the conversion of hydrogen peroxide to water and molecular oxygen, serving to protect cells from its toxic effects [PMID: 11351128]. Hydrogen peroxide is produced as a consequence of oxidative cellular metabolism and can be converted to the highly reactive hydroxyl radical via transition metals, this radical being able to damage a wide variety of molecules within a cell, leading to oxidative stress and cell death. Catalases act to neutralise hydrogen peroxide toxicity, and are produced by all aerobic organisms ranging from bacteria to man. Most catalases are mono-functional, haem-containing enzymes, although there are also bifunctional haem-containing peroxidase/catalases (IPR000763) that are closely related to plant peroxidases, and non-haem, manganese-containing catalases (IPR007760) that are found in bacteria [PMID: 14745498]. Based on a phylogenetic analysis, catalases can be classified into clade 1, 2 and 3. Clade 1 contains small subunit catalases from plants and a subset of bacteria; clade 2 contains large subunit catalases from fungi and a second subset of bacteria; and clade 3 contains small subunit catalases from bacteria, fungi, protists, animals, and plants [PMID: 9287428, PMID: 12557185].

Clade 3 catalases are the most abundant subfamily and are found in all three kingdoms of life; they have a relatively small subunit size of 43 to 75kDa, and bind a protoheme IX (heme b) group buried deep inside the structure. Clade 3 catalases also bind NADPH as a second redox-active cofactor. They form tetramers, and in eukaryotic cells, catalases are located in peroxisomes [PMID: 18498226, PMID: 22209752].

GO terms

Biological Process

GO:0042744 hydrogen peroxide catabolic process
GO:0006979 response to oxidative stress

Molecular Function

GO:0004096 catalase activity
GO:0020037 heme binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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