Occurs in almost all aerobically respiring organisms and serves to protect cells from the toxic effects of hydrogen peroxide. 2 H2O2 = 2 H2O + O2 Activity is predominant during late exponential growth and at the start of the conidiation process. Induced under stress conditions, such as H(2)O(2), paraquat, cadmium, heat shock, uric acid and nitrate treatment. Belongs to the catalase family.