Biochemical and physiological aspects of ubiquinone function

The brief review presents evidences that, in addition to well known functio ns of ubiquinone (coenzyme Q) as a component of the mitochondrial respirato ry chain, this compound in the reduced form (ubiquinol) functions as an ant ioxidant. Ubiquinone in a partially reduced form is found in all cellular m embranes. It efficiently protects not only membrane phospholipids from pero xidation but also mitochondrial DNA and membrane proteins from free-radical induced oxidative damage. This protective role of ubiquinol is independent on the effect of exogenous antioxidants, such as vitamin E, and ubiquinol can both prevent the formation of free lipid radicals and eliminate them ei ther directly or by regenerating vitamin E.