Superoxide dismutase

Superoxide dismutase (SOD) is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide (O2−) 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 and is degraded by other enzymes such as catalase. Thus, SOD is an important antioxidant defense in nearly all living cells exposed to oxygen.

Function

Superoxide dismutase is an important component in the prevention of oxidative stress, a process that can lead to a variety of diseases including cancer, Alzheimer's disease, and Parkinson's disease. The enzyme works by catalyzing the conversion of superoxide radicals into hydrogen peroxide and molecular oxygen, thereby reducing the levels of harmful superoxide radicals in the body.

Structure

There are three major families of superoxide dismutase, depending on the metal cofactor: Cu/Zn (which binds both copper and zinc), Fe and Mn types (which bind either iron or manganese), and the Ni type, which binds nickel.

Clinical significance

Mutations in the first SOD enzyme can cause familial amyotrophic lateral sclerosis (ALS, a form of motor neuron disease). Some research suggests that superoxide dismutase could potentially be used in therapies for age-related skin changes, cancer, and neurodegenerative disorders.

See also

• Antioxidant
• Reactive oxygen species
• Oxidative stress

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