Superoxide dismutase comprises a family of metalloenzymes that catalyze the oxido-reduction of superoxide anion to H2O2. Manganese superoxide dismutase (SOD2) is encoded by nuclear chromatin, synthesized in the cytosol, and imported posttranslationally into the mitochondrial matrix. SOD2 is one of the major cellular defense enzymes that protects against toxic effects of superoxide radicals. Overexpression of human SOD2 has been shown to inhibit radiation-induced neoplastic transformation, suppress malignancy of cancer cells, and increase tolerance to various toxic agents. It has been shown that SOD2 activity in tumor cells is lower than that in their normal counterparts.
