Class III peroxidase (Prx)
Haem peroxidase and IPR002016
plant/fungal/bacterial The profiles do not make distinction between animal and non animal peroxidase and between the different non animal peroxidase classes
Class III peroxidase InterPro: IPR000823
Class III peroxidases or the secreted plant peroxidases (EC 18.104.22.168) are found only in plants, where they form large multigenic families. Although their primary sequence differs in some points from the classes I and II, their three-dimensional structures are very similar to those of class II, and they also possess calcium ions, disulfide bonds, and an N-terminal signal for secretion. Class III peroxidases are additionally able to undertake a second cyclic reaction, called hydroxylic, which is distinct from the peroxidative one. During the hydroxylic cycle, peroxidases pass through a Fe(II) state and use mainly the superoxide anion (O2.-) to generate hydroxyl radicals (.OH). Class III peroxidases, by using both these cycles, are known to participate in many different plant processes from germination to senescence, for example, auxin metabolism, cell wall elongation and stiffening, or protection against pathogens.
Passardi F, Longet D, Penel C, Dunand C. The class III peroxidase multigenic family in rice and its evolution in land plants. Phytochemistry. 2004 Jul;65(13):1879-93. PMID: 15279994