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organic compounds of nonprotein origin that take part in enzyme reactions as acceptors of atoms or groups of atoms split off by the enzyme from a molecule of substrate.

Coenzymes are connected to the protein part of an enzyme molecule, or apoenzyme, by an unstable bond that easily ruptures in the presence of acids and alkalis or during dialysis. The rupture results in the formation of catalytically inactive components.

In general, the formation of a complex involving a coenzyme, a substrate, and an apoenzyme in what is called the active center of the enzyme precedes enzymatic activity. The coenzyme does not undergo irreversible chemical transformation during the catalytic process; therefore, it can participate repeatedly in enzyme reactions. A huge number of biochemical reactions proceed with the participation of a limited set of coenzymes.

The majority of coenzymes are vitamin derivatives or contain vitamins. The chemical nature of the coenzyme largely determines the mechanism and type of enzyme reaction. The coenzymes most widely occurring in animal and plant tissues are nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate, thiamine pyrophosphate, lipoic acid, coenzyme A, adenosine diphosphate, and other nucleoside diphosphates.


Dixon, M., and E. Webb. Fermenty. Moscow, 1966. (Translated from English.)
Moss, D. Fermenty. Moscow, 1970. (Translated from English.)
Bernhard, S.Struktura i funktsiia fermentov. Moscow, 1971. (Translated from English.)


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Oral coenzyme Q10 supplementation improves clinical symptoms and recovers pathologic alterations in blood mononuclear cells in a fibromyalgia patient.
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Coenzyme Q supplementation protects from age-related DNA double-strand breaks and increases lifespan in rats fed on a PUFA-rich diet.
The reduced form of coenzyme Q10 decreases the expression of lipopolysaccharide-sensitive genes in human THP-1 cells.
Modifications of plasma proteome in long-lived rats fed on a coenzyme Q10-supplemented diet.
Effects of coenzyme Q10 supplementation on inflammatory markers (high-sensitivity C-reactive protein, interleukin-6, and homocysteine) in patients with coronary artery disease.
Evaluation of coenzyme Q as an antioxidant strategy for Alzheimer's disease.
Role of concomitant coenzyme Q10 with statins for patients with hyperlipidemia.
Coenzyme Q10 in cardiovascular disease with emphasis on heart failure and myocardial ischaemia.
Is coenzyme Q10 helpful for patients with idiopathic cardiomyopathy?
The effect of coenzyme Q10 in patients with congestive heart failure.
Effect of coenzyme Q10 and ginkgo biloba on warfarin dosage in stable, long-term warfarin treated outpatients.