superoksididismutaasista

Superoksididismutaasista, commonly translated as superoxide dismutase (SOD) in English, is a family of metalloenzymes that catalyze the dismutation of the superoxide radical (O2−) into oxygen (O2) and hydrogen peroxide (H2O2). By converting highly reactive oxygen species into less reactive species, SODs play a central role in cellular antioxidant defense.

Three main isozymes occur in humans: SOD1 (CuZn-SOD) located in the cytosol, SOD2 (Mn-SOD) in the mitochondria, and SOD3 (CuZn-SOD) in the extracellular space. SOD1 is typically a homodimer with copper and zinc cofactors; SOD2 is a tetramer with manganese; SOD3 is a secreted dimer. The canonical reaction is 2 O2− + 2 H+ → H2O2 + O2.

Together with catalase and glutathione peroxidase, SODs limit oxidative damage and influence redox signaling. The distribution of the isozymes supports distinct roles in different cellular compartments and tissues.

Disruption or altered expression of SODs has been linked to aging and several diseases, including amyotrophic lateral sclerosis, Parkinson’s disease, cardiovascular and inflammatory conditions. SOD-targeted therapies—such as mimetic compounds or gene-based strategies—are active areas of research; oral supplementation, however, often yields poor bioavailability.

Historically, the enzyme was discovered in 1969 by McCord and Fridovich, a landmark in free radical biology.