Non Animal peroxidase superfamily: Class I

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Last update: 2019-05-29 (Christophe Dunand)

Class I peroxidase
-Ascorbate peroxidase (APx)
-Catalase peroxidase (CP)
-Cytochrome C peroxidase (CcP)
-Hybrid Ascorbate-Cytochrome C peroxidase (APx-CcP)


Class I peroxidases have been found in plants, fungi, and prokaryotes. They are not glycosylated and do not have signal peptides, calcium ions, or disulfide bridges.
-Ascorbate peroxidase (APx) (EC, L-ascorbate:hydrogen-peroxide oxidoreductase): APx are found in chloroplastic organisms. They show a particularly strong specificity for the electron donor ascorbate. In higher plants, APx are separated, according to their cellular localization, into cytosolic, peroxisomal and chloroplastic.
-Catalase peroxidase (CP) (EC, hydrogen-peroxide:hydrogen-peroxide oxidoreductase): CP or HPI (hydroperoxidase I) or KatG, are mainly present in prokaryotes and marginaly in some fungi and some protists. They are fusion protein and typically have a dual catalytic activity, acting both as a catalase and as a peroxidase. In bateria, they are controlled as part of the OxyR regulon, which senses active oxygen species. the catalatic reaction of catalase-peroxidases takes place via the same two stages reaction of monofunctional catalases.
Enz (Por-FeIII) + H2O2 → Cpd I (Por+.-FeIV = O) + H2O Cpd I (Por+.-FeIV= O) + H2O2 → Enz (Por-FeIII) + H2O + O2
In addition CP can use organic as electron donors for the reduction of compound I to the resting state via two one-electron transfers.
Cpd I(Por+.-FeIV= O) + 2AH2 → Enz(Por-FeIII) + 2AH� + H2O
-Cytochrome C peroxidase (CcP) (EC, ferrocytochrome-c: hydrogen-peroxide oxidoreductase): CcP play a major role scavenging H2O2 generated during aerobic respiration from the oxidation of cytochrome c in the mitochondrial intermembrane space. CcP are abscent from non mitochondrial organisms.
-APx-CcP: hybrid sequences containing APx- and CcP-specific motifs. They have been found mainly in unicellular organisms containing mitochondria and chloroplasts.


Pfam: PF00141
Interpro: IPR010255
Haem peroxidase and IPR002016
Haem peroxidase
plant/fungal/bacterial (non animal peroxidase). The profiles do not make distinction between animal and non animal peroxidases and between the different non animal peroxidase classes.
Class I peroxidase Interpro: IPR000763
Catalase-peroxidase haem and IPR002207
Plant ascorbate peroxidase. The latter profile do not make distinction between Ascorbate peroxidase (APx) and Cytochrome c peroxidase (CcP).


Zamocky M. Phylogenetic relationships in class I of the superfamily of bacterial, fungal, and plant peroxidases. Eur J Biochem. 2004 Aug;271(16):3297-309. PMID: 15291807
Zamocky M, Dunand C. Divergent evolutionary lines of fungal cytochrome c peroxidases belonging to the superfamily of bacterial, fungal and plant heme peroxidases. FEBS Lett. 2006 Dec 11;580(28-29):6655-64. Epub 2006 Nov 16. PMID: 17126331
Passardi F, Zamocky M, Favet J, Jakopitsch C, Penel C, Obinger C, Dunand C. Phylogenetic distribution of catalase-peroxidases: are there patches of order in chaos? Gene. 2007 Aug 1;397(1-2):101-13. Epub 2007 Apr 21. PMID: 17561356
Zamocky M, Gasselhuber B, Furtmuller PG, Obinger C (2014) Turning points in the evolution of peroxidase-catalase superfamily - molecular phylogeny of hybrid heme peroxidases. Cell. Mol. Life Sci. 71:4681-4696