Coenzyme


Coenzyme
A substance that enhances the action of an enzyme. (An enzyme is a protein that functions as a catalyst to mediate and speed a chemical reaction). Coenzymes are small molecules. They cannot by themselves catalyze a reaction but they can help enzymes to do so. In technical terms, coenzymes are organic nonprotein molecules that bind with the protein molecule (apoenzyme) to form the active enzyme (holoenzyme). A number of the water-soluble vitamins such as vitamins B1, B2 and B6 serve as coenzymes.
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A substance (excluding solo metal ions) that enhances or is necessary for the action of enzymes; coenzymes are of smaller molecular size than the enzymes themselves, are dialyzable and relatively heat-stable, and are usually easily dissociable from the protein portion of the enzyme; several vitamins are c. precursors. SYN: cofactor (1).

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co·en·zyme (')kō-'en-.zīm n a thermostable nonprotein compound that forms the active portion of an enzyme system after combination with an apoenzyme compare ACTIVATOR (1)
co·en·zy·mat·ic (.)kō-.en-zə-'mat-ik, -(.)zī- adj
co·en·zy·mat·i·cal·ly -i-k(ə-)lē adv

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n.
a nonprotein organic compound that, in the presence of an enzyme, plays an essential role in the reaction that is catalysed by the enzyme. Coenzymes, which frequently contain the B vitamins in their molecular structure, include coenzyme A, FAD, and NAD.

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co·en·zyme (ko-enґzīm) an organic nonprotein molecule, frequently a phosphorylated derivative of a water-soluble vitamin, that binds with the protein molecule (apoenzyme) to form the active enzyme (holoenzyme).

Medical dictionary. 2011.

Look at other dictionaries:

  • Coenzyme A — Identifiers CAS number …   Wikipedia

  • Coenzyme M — is a coenzyme required for methyl transfer reactions in the metabolism of methanogens.[1][2] The coenzyme is an anion with the formula …   Wikipedia

  • coenzyme — [ koɑ̃zim ] n. m. ou f. • co enzyme 1909; de co et enzyme ♦ Biochim. Substance organique non protéique, qui peut s unir à un apoenzyme pour donner un enzyme actif. Coenzyme A : dérivé de l acide pantothénique jouant un rôle essentiel dans les… …   Encyclopédie Universelle

  • Coenzyme B — IUPAC name 2 [(7 mercapto 1 oxoheptyl)amino] 3 phosphonooxybutanoic acid …   Wikipedia

  • Coenzyme Q-10 — Coenzyme Q10 Coenzyme Q10 Général Nom IUPAC 2,3 diméthoxy 5 méthyl 6 decaprénylbenzoquinone Synonymes …   Wikipédia en Français

  • Coenzyme B — Structure de la coenzyme B Général Nom IUPAC acide 2 [(7 mercapto 1 oxoheptyl)amino] 3 phosphonooxybutanoïque …   Wikipédia en Français

  • coenzyme A — co*en zyme A (k[ o]*[e^]n z[imac]m [=a] ), (Biochem.) a coenzyme ({C21H36N7O16P3S}) that participates in the transfer of acetyl groups in biochemical reactions; abbreviated {CoA}. It contains adenosine, phosphate, pantothenic acid and cysteamine… …   The Collaborative International Dictionary of English

  • Coenzyme Q ou Co Q — ● Coenzyme Q ou Co Q coenzyme intervenant dans la chaîne des transferts d électrons intracellulaires chaîne respiratoire …   Encyclopédie Universelle

  • coenzyme — co*en zyme (k[ o]*[e^]n z[imac]m), (Biochem.) a molecule that is essential for the activity of some enzymes; it may exist free in solution within a living organism, but functions by binding to an enzyme to assist in catalyzing a reaction. The… …   The Collaborative International Dictionary of English

  • coenzyme A — coenzyme A. См. кофермент А. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • coenzyme Q — coenzyme Q. См. убихинон. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.


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