Decomposes hydrogen peroxide into water and oxygen; serves to protect cells from the toxic effects of hydrogen peroxide. Could protect cells in nodules which have a high potential to produce hydrogen peroxide because of the strong reducing conditions required for nitrogen fixation and the action of several proteins. 2 H2O2 = 2 H2O + O2 By hydrogen peroxide. Either KatA or KatC is absolutely required for the protection of the nitrogen fixation process. Belongs to the catalase family.