Bifunctional enzyme with both catalase and broad-spectrum peroxidase activity. AH2 + H2O2 = A + 2 H2O 2 H2O2 = 2 H2O + O2 Binds 1 heme b (iron(II)-protoporphyrin IX) group per monomer. Inhibited by KCN. Optimum pH is 4.75 for the peroxidase reaction and 6.25 for the catalase reaction. Homodimer or homotetramer. Induced in late stationary growth phase. 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.