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. Can use NADH, NADPH and monolignols as substrates. 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. Optimum pH is 4.7. Expressed at a high level in roots and at a trace level in lower leaves. Not expressed in upper leaves, stems, flowers, seeds and shoot apices. Induced rapidly in leaves after wounding, mRNA is detectable 30 minutes after wounding, reaches maximum levels after 4 hours, and decreases slightly after 8 hours. When lower leaves are wounded, mRNA also accumulates in upper, unwounded, leaves. Wound-induced expression is enhanced by spermine, and suppressed by methyl jasmonite and coronatine. Salicylic acid and ethephon have no effect on wound-induced expression. Induced by infection with TMV. Belongs to the peroxidase family. Classical plant (class III) peroxidase subfamily.