In organic chemistry, acetyl is a functional group, the acyl with chemical formula COCH3. It is sometimes abbreviated as Ac (not to be confused with the element actinium). The acetyl group contains a methyl group single-bonded to a carbonyl. The carbonyl center of an acyl radical has one nonbonded electron with which it forms a chemical bond to the remainder R of the molecule. In IUPAC nomenclature, acetyl is called ethanoyl, although this term is rarely heard. The acetyl moiety is a component of many organic compounds, including the neurotransmitter acetylcholine, acetyl-CoA, acetylcysteine, and the analgesics acetaminophen and acetylsalicylic acid (better known as aspirin).
The introduction of an acetyl group into a molecule is called acetylation. In biological organisms, acetyl groups are commonly transferred to coenzyme A (CoA) and from acetyl-CoA. Acetyl-CoA is an intermediate both in the biological synthesis and in the breakdown of many organic molecules. In synthetic organic chemistry,
Histones and other proteins are often modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of chromatin architecture, allowing for genetic transcription to occur. However, removal of the acetyl group by histone deacetylases (HDACs) condenses DNA structure, thereby preventing transcription. In addition to HDACs, Methyl group additions are able to bind DNA resulting in DNA methylation, and this is another common way to block DNA acetylation and inhibit gene transcription.
Synthetic organic and pharmaceutical chemistry
Acetylation can be achieved using a variety of methods, the most common one being via the use of acetic anhydride or acetyl chloride, often in the presence of a tertiary or aromatic amine base. A typical acetylation is the conversion of glycine to acetylglycine:
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