Superoxide dismutases (SOD) are enzymes that alternately catalyze the dismutation (or partitioning) of the superoxide radical into either ordinary molecular oxygen (O2) or hydrogen peroxide (H2O2).
Superoxide is produced as a by-product of oxygen metabolism and, if not regulated, causes many types of cell damage. Hydrogen peroxide is also damaging, but less so, and is degraded by other
enzymes such as catalase. Thus, SOD is an important antioxidant defense in nearly all living cells exposed to oxygen.
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