Search results
Results From The WOW.Com Content Network
Plastoquinone (PQ) is a terpenoid-quinone (meroterpenoid) molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis. The most common form of plastoquinone, known as PQ-A or PQ-9, is a 2,3-dimethyl-1,4- benzoquinone molecule with a side chain of nine isoprenyl units.
Ubiquinone-10 is a naturally occurring 1,4-benzoquinone involved in respiration apparatus. Plastoquinone is a redox relay involved in photosynthesis. Pyrroloquinoline quinone is another biological redox cofactor. Ubiquinones, as their name implies, are ubiquitous in living creatures, being components of respiratory apparatus.
In the early 2000s, a group of researchers led by prof V. P. Skulachev in Moscow State University began the development of SkQ — the mitochondrial-targeted antioxidant, similar to MitoQ, but with the ubiquinone replaced with plastoquinone (more active analog of ubiquinone derived from plant chloroplasts). [9]
The electrons are transferred to plastoquinone and two protons, generating plastoquinol, which released into the membrane as a mobile electron carrier. This is the second core process in photosynthesis. The initial stages occur within picoseconds, with an efficiency of 100%. The seemingly impossible efficiency is due to the precise positioning ...
The oxidase catalyzes the transfer of four electrons from reduced plastoquinone to molecular oxygen to form water. The net reaction is written below: 2 QH 2 + O 2 → 2 Q + 2 H 2 O Analysis of substrate specificity revealed that the enzyme almost exclusively catalyzes the reduction of plastoquinone over other quinones such as ubiquinone and ...
Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the energy-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants , algae , and cyanobacteria .
Electron-transferring-flavoprotein dehydrogenase (ETF dehydrogenase or electron transfer flavoprotein-ubiquinone oxidoreductase, EC 1.5.5.1) is an enzyme that transfers electrons from electron-transferring flavoprotein in the mitochondrial matrix, to the ubiquinone pool in the inner mitochondrial membrane.
Ubiquinone (Q), in turn, binds the Q i site of complex III. Ubiquinol is divergently oxidized (gives up one electron each) to the Rieske iron-sulfur '(FeS) protein' and to the b L heme. This oxidation reaction produces a transient semiquinone before complete oxidation to ubiquinone, which then leaves the Q o site of complex III.