Superoxide dismutase (SOD) is responsible for the elimination of cytotoxic active oxygen by catalyzing the dismutation of the superoxide radical to oxygen and hydrogen peroxide. There are three SOD isoenzymes in mammalian cells: extracellular SOD (EC SOD, SOD-3), copper and zinc-containing SOD (Cu/Zn SOD, SOD-1), and manganese-containing SOD (Mn SOD, SOD-2). Mn SOD is an 80kD homotetramer that contains Mn ions and resides in the mitochondrial matrix. Mn SOD is a tumor necrosis factor (TNF)-inducible enzyme that protects cells from TNF-mediated apoptosis via superoxide anion detoxification, and the subsequent regulation of apoptosis through cytochrome c release and modulation of the redox state of the mitochondria. Overexpression of this enzyme protects neurons from NMDA- and nitric oxide-induced neurotoxicity. Applications: Suitable for use in Western Blot and Immunohistochemistry. Other applications have not been tested. Recommended Dilutions: Western Blot (Colorimetric): 1:1000 Optimal dilutions to be determined by researcher. Positive Control: Human skeletal muscle Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.