Removal of H(2)O(2), oxidation of toxic reductants, biosynthesis and degradation of lignin, suberization, auxin catabolism, response to environmental stresses such as wounding, pathogen attack and oxidative stress. These functions might be dependent on each isozyme/isoform in each plant tissue. Exhibits a Ca(2+)-pectate binding affinity which could be interpreted in vivo as a specificity to interact with the pectic structure of the cell wall. 2 a phenolic donor + H2O2 = 2 a phenolic radical donor + 2 H2O Binds 1 heme b (iron(II)-protoporphyrin IX) group per subunit. Binds 2 calcium ions per subunit. A number of isoforms are produced. According to EST sequences. Expressed in roots and leaves. Up-regulated during leaf development. Enhanced expression in response of mechanical wounding. Induced either by incompatible fungal pathogen attack, or by methyl jasmonate, a plant defense-related signaling molecule. Expressed under a diurnal rhythm (circadian clock control). There are 73 peroxidase genes in A.thaliana. Belongs to the peroxidase family. Classical plant (class III) peroxidase subfamily.