Coenzyme Q10
- All-trans- 6- decaprenyl -2 ,3- dimethoxy- 5-methyl- 1 ,4-benzoquinone (IUPAC / IUBMB )
- Q-10
- Obsolete: Coenzyme Q10
C01EB09
Fixed
50 ° C.
Template: Infobox chemical / molecular formula search available
Ubiquinone -10 ( UQ of Engl. Ubiquinone or Q 10 or CoQ10 ) is a quinone derivative with lipophilic isoprenoid side chain, structurally related to vitamin K and vitamin E. The reduced, phenolic form is Ubihydrochinon or ubiquinol (short QH2 ) called. Ubiquinone -10 is one of the ubiquinones.
Q-10 is an electron and proton carrier between the complex I or complex II and the complex III of the respiratory chain.
Q-10 is available as a component of cosmetic creams, and also for sale as a dietary supplement.
Properties
Q -10 is a yellow-orange crystalline powder without smell and taste.
The hydrophobic side chain isoprenoid allows the anchorage of the molecule in the hydrophobic region of the biomembranes are also constituting the mitochondria.
Biological Function
Q -10 is an endogenous substance. It is added to the part about the food, but also produced in the body itself. In each human cell, the energy is converted from the diet in endogenous energy (ATP). Q-10 is involved as coenzyme in the oxidative phosphorylation, about 95% of the total body energy (ATP) is generated. The organs with the highest energy requirements - such as heart, lungs and liver - therefore also have the highest Q- 10 concentration.
Biochemistry
The respiratory chain in the mitochondria of the cell, enables the gradual transfer of electrons and protons on oxygen with simultaneous production of ATP as a biochemical energy equivalent. This reaction sequence, which is sometimes referred to as "controlled detonating gas reaction " takes place at localized membrane proteins, the complexes I to V, and mobile components, ubiquinone and cytochrome c instead. The latter serve as shuttle systems between the complexes: ubiquinone mediates between complexes I / II and III, cytochrome c between complexes III and IV
The electrons for the reduction of ubiquinone come from the oxidation of NADH at the complex I of the respiratory chain NADH dehydrogenase, or from the oxidation of succinate at complex II, which is identical with the succinate dehydrogenase of the citric acid cycle. A ubiquinone molecule can accommodate two electrons gradually. In the first step, QH •, a fairly stable semiquinone radical forms. Receiving the second electron can after protonation hydroquinone ubiquinol created, that is the reduced form. In addition to the electron transport, this allows also the binding of two protons - ubiquinone may thus also serve as a proton carrier. These operations are within the respiratory chain in the Q cycle at complex III of importance.
Pro-oxidant and antioxidant properties
Ubiquinone is also involved in the formation of reactive oxygen species (ROS) by the formation of superoxide radicals by Ubisemichinon that cause oxidative damage that is many degenerative diseases is based. Paradoxically, the ubiquinone pool is also an important mitochondrial antioxidant.
A permanent Q-10 deficiency is rare. It is found more frequently in patients with myopathies. Since the enzymes involved in the biosynthesis of Q-10 are not yet fully known, it is readily possible that mutations in one of the genes involved have not yet been identified.
A way for temporary Q 10 deficiency, the medication is with a statin, in which the starting materials for the biosynthesis of Q-10 is reduced by inhibition of HMG -CoA reductase, which leads to a decrease in the plasma levels. About the availability of Q -10 in the muscle, however, nothing is known, as little as a efficacy of increased supply.
Biosynthesis
The biosynthesis of Q-10 in eukaryotes involves both from 4-hydroxybenzoic acid, which is derived from the amino acid tyrosine into five steps, including through Hydroxyphenylbernsteinsäure and 4- coumaric acid, obtained and forms the quinone moiety; on the other hand all-trans- Decaprenylphosphat is required for the side chain, which is composed of Geranylgeranylphosphat ( GGP, from the mevalonate pathway ) in six steps. Both starting materials together using the p- hydroxybenzoate Polyprenyltransferase ( EC 2.5.1.39 ) to 3 - decaprenyl -4 -hydroxybenzoate. In seven additional steps arises ubiquinol -10, which is to ubiquinone -10 by electron transfer.
Nutritional Supplements
About the food takes a person a day about three to five milligrams of coenzyme on what is not absolutely necessary. Its only increased Q-10 needs can help to avoid or compensate for a lack a nutritional supplement. For adults, the recommended by most scientists in such a case dose of Q -10 is a dietary supplement 30-200 mg per day. The Federal Office of Consumer Protection and Food Safety features that may be put into circulation in Germany dietary supplements in capsule form with Q-10, when " the daily intake of 100 mg of coenzyme Q10 at a Recommended dosage of one capsule per day is not exceeded " and the labeling prior to consumption by pregnant women, nursing mothers, children under 18 years warns.
Cosmetics
Q-10 is also propagated active ingredient often offered skin creams. They are intended to offset the allegedly increasing the age lack of Q -10 and ensure the elimination of harmful radicals, for example.
Occurrence
Q-10 is found rich in meat of organs (liver), oily fish ( sardines, mackerel, etc.), nuts (such as pistachios ), pulses, sesame seeds, sunflower seeds, vegetable oils, cabbage, onions, potatoes, spinach, Brussels sprouts and broccoli. However, cooking can destroy the coenzyme.
Production
For the production of Q- 10, three methods are used: the fermentation of yeast, bacteria fermentation and chemical synthesis.
When Hefefermentationsverfahren arises Q -10 in the so-called trans configuration, which means that it is identical to the naturally occurring CoQ10, such as is found in meat, fish or other foods.
The security of yeast fermentation was confirmed by several safety studies that have been carried out by one of the world's leading test laboratories ( Covance Laboratories Inc.). Furthermore, it was demonstrated in a double-blind, randomized, placebo-controlled study that CoQ10 is of yeast fermentation in doses up to 900 milligrams per day absolutely safe and well tolerated.
Prepared by chemical synthesis the Q-10 containing the cis- isomer ( a naturally occurring in the Q-10 not existing molecular structure), whose security is no intensive studies have been carried out.
History
Ubiquinone -10 was discovered in 1957 and first isolated by Fred L. Crane from bovine heart. The chemical structure was elucidated from Karl August Folkers 1958. For insights into the role of Q -10 in the Q cycle of complex III of the respiratory chain, the British scientist Peter D. Mitchell was awarded the 1978 Nobel Prize in Chemistry.