Catalases ( EC:1.11.1.6 ) are antioxidant enzymes that catalyse the conversion of hydrogen peroxide to water and molecular oxygen, serving to protect cells from its toxic effects [ PUBMED:11351128 ]. Hydrogen peroxide is produced as a consequence of … expand

Catalases ( EC:1.11.1.6 ) are antioxidant enzymes that catalyse the conversion of hydrogen peroxide to water and molecular oxygen, serving to protect cells from its toxic effects [ PUBMED: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 [ PUBMED: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 [ PUBMED:9287428 PUBMED:12557185 ].

This entry represent the core-forming domain of mono-functional, haem-containing catalases. It does not cover the region that carries an immune-responsive amphipathic octa-peptide that is found in the C-terminal of some catalases ( IPR010582 ).