Decomposes hydrogen peroxide into water and oxygen; serves to protect cells from the toxic effects of hydrogen peroxide. 2 H2O2 = 2 H2O + O2 Elevated levels of expression during entry into the stationary phase of the growth cycle. By hydrogen peroxide. Insertion mutant shows increased sensitivity to H(2)0(2), reduced catalase expression and an absence of induced protection of the cell. Belongs to the catalase family.