The Various Sources of Mitochondrial Oxygen Radicals: A Minireview

The mitochondrial respiratory chain is the main source of reactive oxygen species in the cell. The main sites of superoxide radical production are within Complexes I and III; however, Complex II, glycerol phosphate dehydrogenase and dihydroorotate dehydrogenase, are also sources of oxygen radicals. By using specific inhibitors within the complexes it is possible to obtain indications at the sites where redox components react with oxygen and in the compartments where they are released. The production of oxygen radicals is enhanced when the electron flow is lowered, and partial uncoupling is believed to be a means of preventing excess radical production.