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. 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. Expressed in the whole plant, with the highest expression in roots. Up-regulated transiently by a cold treatment. There are 73 peroxidase genes in A.thaliana. Belongs to the peroxidase family. Classical plant (class III) peroxidase subfamily.