Structure. Ubiquinones (coenzyme Q, mitoquinones, CoQ, or UQ) belong to the group of quinones within the prenol lipids category. Their structure consists of a single- or double-ring structure linked to a chain made of five-carbon isoprene units, the building blocks of prenol lipids. Both, the ring structure and the isoprene chain may encompass oxygen containing substituents, the ring structure may further contain hydrocarbon substituents.
Function. Ubiquinones are found in all living organisms. Their most prominent and essential biological function is to act as electron carriers between membrane-bound proteins within the electron transport chain to synthesize ATP, the energy-carrying molecule. In plants, ubiquinones that are providing an electronic connection system for the generation of ATP through photosynthesis are called plastoquinones. Further, ubiquinones possess antioxidant properties protecting membrane proteins and DNA against oxidative damage.
