COQ2 (coenzyme Q2, polyprenyltransferase), also known as CL640. It is expected to be located in mitochondrion inner membrane. And the protein is highly expressed in skeletal muscle, adrenal glands and the heart. COQ2 is a redox carrier in the mitochondrial respiratory chain and a lipid-soluble antioxidant. This enzyme, which is part of the coenzyme Q10 pathway, catalyzes the prenylation of parahydroxybenzoate with an all-trans polyprenyl group. Mutations in this gene cause coenzyme Q10 deficiency, a mitochondrial encephalomyopathy, and also COQ2 nephropathy, an inherited form of mitochondriopathy with primary renal involvement. The protein has three isforms, the calculated molecular weight are 35, 40, 45 kDa.