Superoxide Dismutase

The enzyme superoxide dismutase, catalyzes the dismutation of superoxide into oxygen and hydrogen peroxide. It is an important antioxidant defense in nearly all cells exposed to oxygen.

SOD can be naturally found in the cytosols of all eukaryotic cells with copper and zinc. It is in chicken liver (and nearly all other) mitochondria. Many bacteria contain a form with manganese (Mn-SOD).

SOD out-competes damaging reactions of superoxide, thus protecting the cell from superoxide toxicity. Superoxide is one of the main reactive oxygen species in cells. The physiological importance of SODs is illustrated by the severe pathologies evident in mice genetically engineered to lack these enzymes.

Mutations in the first SOD enzyme can cause familial amyotrophic lateral sclerosis (ALS). Overexpression of SOD1 has been linked to Down’s syndrome.

SOD has proved to be highly effective in treatment of colonic inflammation in experimental colitis and may be an important new tool for the treatment of inflammatory bowel disease. It is used in cosmetic products to reduce free radical damage to skin. Having adequate zinc (about 15 mg a day) and copper (1/2 mg a day) are key nutrients responsible for optimal SOD function. Too much copper, however, can actually increase oxidative stress, so more is not better.

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