SOD2 (superoxide dismutase 2, mitochondrial, MnSOD ) is a mitochondrial protein that converts toxic superoxide byproducts and to diatomic oxygen and hydrogen peroxide. It functions to clear reactive oxygen species in the mitochondria and thus it plays an important role in protecting against apoptosis, cell death and oxidative stress. Mutations in SOD2 may lead to a number of diseases including idiopathic cardiomyopathy, cancer, premature aging syndromes, and neurodegenerative diseases including Alzheimer’s, Parkinson’s, and sporadic motor neuron disease. In immunohistochemistry, SOD2 has granular cytoplasmic positivity in all tissues. References: J Bio Chem. 278 (15): 13294–301. doi:10.1074/jbc.M208670200, PMID: 12551919; Biochemistry. 48 (15): 3417–24. doi:10.1021/bi8023288, PMID: 19265433; Free Radic Biol Med. 2013 Sep;62:4-12, PMID: 23727323