Bifunctional enzyme with both catalase and broad-spectrum peroxidase activity. Confers resistance to H(2)O(2) in hyphae. May play an antioxidative role in fungal defense against the host-produced H(2)O(2) (oxidative burst) at the early stage of plant infection. AH2 + H2O2 = A + 2 H2O 2 H2O2 = 2 H2O + O2 Binds 1 heme b (iron(II)-protoporphyrin IX) group per monomer. kcat is 6446 sec(-1) with H(2)O(2) as substrate at pH 5.25 and 3290 sec(-1) with H(2)O(2) as substrate at pH 7.0. Optimum pH is 5.25 for the catalase reaction. Stable from pH 5.5 to pH 11. Homodimer; disulfide-linked. Formation of the three residue Trp-Tyr-Met cross-link is important for the catalase, but not the peroxidase activity of the enzyme. Belongs to the peroxidase family. Peroxidase/catalase subfamily.