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 2 calcium ions per subunit. Binds 1 heme b (iron(II)-protoporphyrin IX) group per subunit. Exhibits smaller absorbance peaks at 497 and 635 nm. After treatment with stoichiometric amounts of hydrogen peroxide the absorption maximum is shifed to 400 nm. Optimum pH is 5.5. Retains more than 50% of activity between pH 4 and 7. The measured mass is that of the phosphorylated and glycosylated protein. Belongs to the peroxidase family. Classical plant (class III) peroxidase subfamily.