Abstract
As an indispensable factor in the mitochondrial respiratory chain, the role of coenzyme Q has been conclusively established. However, the details of the mechanism of how it functions are under investigation. The proton motive Q cycle theory proposed by Mitchell has stimulated the research on topology of coenzyme Q in mitochondrial membranes. The biosynthesis of coenzyme Q is considered in relation to that of cholesterol because they are derived from the same precursor, mevalonate.
The clinical application of coenzyme Q10 to diseases supposed to be brought about by mitochondrial dysfunction has been developed, particularly in Japan. The physiological significance of exogenous coenzyme Q10 is discussed as a supplier of coenzyme Q10 to endogenous coenzyme Q pool in mitochondria, a membrane stabilizer and an antioxidant.