The various enzymes with molecular weights from 32,000 to 56,000 Da have metal ions, such as copper and zinc (Cu???Zn-SOD), manganese (Mn-SOD) or iron (Fe-SOD) as co-factors in the catalytic centre. 2O2 ???+2H+???H2O2+O2tm (2) [0031] The hydrogen peroxide formed by reaction of the SOD is then converted into water and oxygen in a multi-stage catalytic cycle by the redox enzyme catalase, which is ub