coenzyme Q

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an organic molecule, usually containing phosphorus and some vitamins, sometimes separable from the enzyme protein; a coenzyme and an apoenzyme must unite in order to function (as a holoenzyme).
coenzyme A a coenzyme essential for carbohydrate and fat metabolism; among its constituents are pantothenic acid and a terminal SH group, which forms linkages with various acids, e.g., acetic acid (acetyl CoA) and fatty acids (acyl CoA); abbreviated CoA.
coenzyme Q any of a group of related quinones occurring in the lipid fraction of mitochondria and serving, along with the cytochromes, as an intermediate in electron transport; they are similar in structure and function to vitamin K1.

co·en·zyme Q (CoQ, Q),

Designation applied to ubiquinones with isoprenoid side chains consisting of variable numbers of isoprene units. CoQ mediates electron transfer between cytochromes b and c, and is chemically similar to vitamins E and K and to other tocopherols, quinones, and tocols. the length of the isoprenoid side chain distinguishes one type of CoQ from another; for example, ubiquinone-10, the typical mammalian ubiquinone, has a side-chain of 10 isoprene units.

coenzyme Q


co·en·zyme Q

Quinones with isoprenoid side chains (specifically, ubiquinones) that mediate electron transfer between cytochrome b and cytochrome c.

coenzyme Q (ubiquinone)

a quinone derivative with a variable length isoprenoid side chain at position 6 on the molecule. Ubiquinone is an oxidation-reduction COENZYME that functions in the respiratory ELECTRON TRANSPORT SYSTEM as a carrier of electrons between DEHYDROGENASES and CYTOCHROMES.
References in periodicals archive ?
Turunen M, Olsson J, Dallner G, 2004, Metabolism and function of coenzyme Q. Biochimica Biophysica Acta.
Biosynthesis of the isoprenoid quinones menaquinone (vitamin K2) and ubiquinone (coenzyme Q).
Bioenergetics in clinical medicine II: adjunctive treatment with coenzyme Q in periodontal therapy.