Oxidative stress와 질병

Free radicals are produced continuously at a high rate as a by-product of aerobic metabolism. Free radicals including hydroxyl radical (OH-), H, superoxide (O2), hydroperoxide (HO2)， and CO2 are very reactive and oxidize other molecules such as DNA, lipids, and proteins. These oxidized products, lipid peroxides and lipid hydroperoxides, are oxidative damage, which should be removed. Under normal conditions, a multi- level antioxidant defence system removes reactive oxygen species. The an tioxidant defense system is consisting of antioxidant enzymes (superoxide dismutase, catalase, glutathion peroxidase, glutathion reductase) and free radical scavengers (vitamin E). Consequently, in good health, the exposure of biomolecules to non-specific oxidation by free reactive oxygen spec ie s appears to be minimal.