A widely distributed enzyme that removes the superoxide radical (O2·), with the formation of molecular oxygen and hydrogen peroxide, in the following reaction:
O2· + O2· + 2H+ → O2 + H2O2
The hydrogen peroxide formed is removed by the action of catalase. The superoxide anion, which damages tissues, is a free radical formed by the partial reduction of molecular oxygen and a normal by-product of aerobic respiration in mitochondria. It is also produced during the metabolic breakdown of various toxins (including drugs and chemical poisons) and as part of the immune response to the presence of bacteria and virus-infected cells. See oxidative burst.
Subjects: Medicine and Health — Biological Sciences.