Ubiquinone biosynthesis protein COQ7 homolog, also known as Coenzyme Q biosynthesis protein 7 homolog, Timing protein clk-1 homolog and COQ7, is a mitochondrion inner membrane and peripheral membrane protein which belongs to the COQ7 family. It is expressed dominantly in heart and skeletal muscle. COQ7 is synthesized as a preprotein that is imported into the mitochondrial matrix, where the sequence is cleaved off and the mature protein becomes loosely associated with the inner membrane. This enzyme is responsible for the hydroxylation of 5-demethoxyubiquinone to 5-hydroxyubiquinone. Human COQ7 protein is mostly helical, and contains an alpha-helical membrane insertion. It has a potential N-glycosylation site, a phosphorylation site for protein kinase C and another for casein kinase II, and three N-myristoylation sites. COQ7 is involved in lifespan determination in ubiquinone-independent manner. It is also involved in ubiquinone biosynthesis. COQ7 is potential central metabolic regulator.