In organic chemistry, acetyl (ethanoyl), is a functional group, the acyl of acetic acid, with chemical formula -COCH3. It is sometimes abbreviated as Ac (not to be confused with the element actinium). The acetyl radical contains a methyl group single-bonded to a carbonyl. The carbon of the carbonyl has a lone electron available, with which it forms a chemical bond to the remainder "R" of the molecule.

The acetyl radical is a component of many organic compounds, including the neurotransmitter acetylcholine, and acetyl-CoA, and the analgesics acetaminophen and acetylsalicylic acid (better known as aspirin).


The introduction of an acetyl group into a molecule is called acetylation (or ethanoylation). In biological organisms, acetyl groups are commonly transferred bound to Coenzyme A (CoA), in the form of acetyl-CoA. Acetyl-CoA is an important intermediate both in the biological synthesis and in the breakdown of many organic molecules.

Acetyl groups are also frequently added to histones and other proteins modifying their properties. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of chromatin architecture allowing for genetic transcription to take place. Conversely, removal of the acetyl group by histone deacetylases (HDACs) condenses DNA structure, thereby preventing transcription. [cite journal |author=North B, Verdin E |title=Sirtuins: Sir2-related NAD-dependent protein deacetylases |journal=Genome Biol |volume=5 |issue=5 |pages=224 |year=2004 |pmid=15128440 | doi = 10.1186/gb-2004-5-5-224]

Chemical acetylation can be achieved using a variety of methods, most commonly by the use of acetic anhydride or acetyl chloride in the presence of a tertiary or aromatic amine base.


When acetyl groups are bound to certain other organic molecules, they impart an increased ability to cross the blood-brain barrier. This makes the drug reach the brain more quickly, making the drug's effects more intense and increasing the effectiveness of a given dose. Acetyl groups are used to make the natural anti-inflammatant salicylic acid into the more effective acetylsalicylic acid, or aspirin. Similarly, they make the natural painkiller morphine into diacetylmorphine, or heroin.

Most recently, the supplement industry touts acetyl-L-carnitine as being more effective than other preparations of carnitine. Also, research on irradiated rodents shows resveratrol attached to acetyl as holding promise as one of the first anti-radiation medicines for human populations. For citation, see the webpage article of


See also

*Acetoxy group
*Functional group
*Histone acetylation and deacetylation
*Polyoxymethylene plastic, a.k.a. acetal resin, a thermoplastic

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  • acétyl- — ⇒ACÉTYL , élément préf. [Tiré de acétyle] CHIM. Indique que le rad. CH3 CO s est substitué dans une molécule organique à un atome d hydrogène (en chim., on emploie acétyl de préférence à acéto ) : acétylacétate d éthyle « liquide incolore à odeur …   Encyclopédie Universelle

  • Acetyl — Acetyl, ein hypothetisches Radical, welches mit Sauerstoff das Acetyloxydhydrat, das Acetat, die acetylige Säure und in seiner höchsten Verbindung mit Sauerstoff die Acetyl oder Essigsäure bildet …   Herders Conversations-Lexikon

  • Acetyl — Ac e*tyl, n. [L. acetum vinegar + Gr. ? substance. See { yl}.] (Chem.) A complex, hypothetical radical, composed of two parts of carbon to three of hydrogen and one of oxygen. Its hydroxide is acetic acid. [1913 Webster] …   The Collaborative International Dictionary of English

  • Acetyl — (Chem.), ist das hypothet. Radical der Essigsäure u. der übrigen Acetylverbindungen. Nach Kolbe ist das A. ein gepaartes Radical, bestehend aus Methyl C2H3 u. Kohlenstoff 2C, daher C4H3; nach Gerhardt ist es sauerstoffhaltig u. besteht aus C4H3O2 …   Pierer's Universal-Lexikon

  • Acetȳl — Acetȳl, die Atomgruppe CH3.CO, die in vielen Verbindungen vorkommt, wie im Aldehyd CH3.COH, in der Essigsäure CH3.COOH etc …   Meyers Großes Konversations-Lexikon

  • Acetyl — Acetyl, s. Aldehyde …   Lexikon der gesamten Technik

  • Acetyl — Cellulose acetate silk (see Celanese) …   Dictionary of the English textile terms

  • acetyl — [ə sēt′ l; as′ə til΄, as′ətəl, as′ətēl΄] n. [ ACET(IC) + YL] the radical CH3CO, derived from acetic acid: found only in compounds acetylic [as΄ə til′ik] adj …   English World dictionary

  • Acetyl — Acetylgruppe Der Begriff Acetylgruppe bezeichnet die chemische Struktur −CO−CH3, die sich aus der Carbonyl und Methylgruppe zusammensetzt. Sie kommt in sehr vielen natürlichen (biologischen) und synthetischen Molekülen, z. B. Acetylsalicylsäure… …   Deutsch Wikipedia

  • Acetyl — Acétyle Le groupe acétyle est le groupement acyle de l acide acétique. Sa formule chimique est COCH3, parfois écrite Ac (à ne pas confondre avec l élément chimique actinium). Une molécule contenant le groupe acétyle a la structure chimique… …   Wikipédia en Français

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