Catalase (CAT) catalyzes the conversion of hydrogen peroxide to water and oxygen. CAT contains porphyrin-heme Fe group which reacts with the hydrogen peroxide. CAT containing Mn are called pseudocatalase (PCAT).[1] Catalase-peroxidase (CAT KatG) is a bifunctional enzyme with both catalase and peroxidase activities. CAT KatG cofactor is a heme group. It provides defense against oxidative stress by reducing hydrogen peroxide. Mutations in CAT KatG can cause resistance to the anti-malarial drug isoniazid (INH).[2] Catalase-phenol oxidase (CATPO) is a heme-containing CAT which shows phenol oxidase activity.[3]


Catalase is a , each over 500 amino acids long. It contains that allow the enzyme to react with the hydrogen peroxide. in E. coli catalase.[4]

As hydrogen peroxide enters the active site, it interacts with the amino acids Asn147 (asparagine at position 147) and His74, causing a proton (hydrogen ion) to transfer between the oxygen atoms. The free oxygen atom coordinates, freeing the newly formed water molecule and Fe(IV)=O. Fe(IV)=O reacts with a second hydrogen peroxide molecule to reform Fe(III)-E and produce water and oxygen. The reactivity of the iron center may be improved by the presence of the phenolate ligand of Tyr357 in the fifth iron ligand, which can assist in the oxidation of the Fe(III) to Fe(IV). The efficiency of the reaction may also be improved by the interactions of His74 and Asn147 with reaction intermediates.[5]

See more details in Ann Taylor/Catalase and Catalase 2CAG bcce2014.
See also Catalase (Hebrew).

E. coli catalase Hpii tetramer showing the heme group, 1gge

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3D Structures of catalase3D Structures of catalase

Updated on 06-December-2015

ReferencesReferences

  1. Purwar N, McGarry JM, Kostera J, Pacheco AA, Schmidt M. Interaction of Nitric Oxide with Catalase: Structural and Kinetic Analysis. Biochemistry. 2011 May 6. PMID:21524057 doi:10.1021/bi200130r
  2. Bertrand T, Eady NA, Jones JN, Jesmin, Nagy JM, Jamart-Gregoire B, Raven EL, Brown KA. Crystal structure of Mycobacterium tuberculosis catalase-peroxidase. J Biol Chem. 2004 Sep 10;279(37):38991-9. Epub 2004 Jul 1. PMID:15231843 doi:10.1074/jbc.M402382200
  3. Koclar Avci G, Coruh N, Bolukbasi U, Ogel ZB. Oxidation of phenolic compounds by the bifunctional catalase-phenol oxidase (CATPO) from Scytalidium thermophilum. Appl Microbiol Biotechnol. 2013 Jan;97(2):661-72. doi: 10.1007/s00253-012-3950-2., Epub 2012 Feb 28. PMID:22370948 doi:http://dx.doi.org/10.1007/s00253-012-3950-2
  4. Melik-Adamyan W, Bravo J, Carpena X, Switala J, Mate MJ, Fita I, Loewen PC. Substrate flow in catalases deduced from the crystal structures of active site variants of HPII from Escherichia coli. Proteins. 2001 Aug 15;44(3):270-81. PMID:11455600
  5. Melik-Adamyan W, Bravo J, Carpena X, Switala J, Mate MJ, Fita I, Loewen PC. Substrate flow in catalases deduced from the crystal structures of active site variants of HPII from Escherichia coli. Proteins. 2001 Aug 15;44(3):270-81. PMID:11455600

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Michal Harel, Alexander Berchansky, Ann Taylor, Karsten Theis