Acetyl

Acetyl refers to the acetyl group, a two‑carbon acyl substituent with the formula CH3–CO–. It is derived from acetic acid and is often written as Ac–. In a molecule, the acetyl group is attached through the carbonyl carbon, forming esters, amides, or thioesters such as R–O–CO–CH3 (acetate esters), R–CO–NH–CH3 (N‑acetyl amides), or R–S–CO–CH3 (thioesters).

Acetylation is a common chemical and biological transformation. In synthesis, acetyl groups are introduced to protect or modify functional groups or to change properties like solubility. They are removed or transformed in subsequent steps. In biology, acetyl groups are carried by coenzyme A as acetyl‑CoA, a central donor of acetyl units in metabolism. Acetyl groups are transferred to various substrates by acetyltransferase enzymes. Protein acetylation, including histone acetylation, influences enzyme activity and gene expression, and it can be reversed by deacetylases, allowing dynamic regulation.

Related reagents used to introduce acetyl groups include acetyl chloride (CH3COCl) and acetic anhydride ((CH3CO)2O). These reagents enable the formation of acetylated products in both laboratory synthesis and industrial processes.

Summary: the acetyl group is a two‑carbon acyl substituent derived from acetic acid, essential in chemistry for modifying and protecting molecules, and a key unit in biology for metabolism and regulation through acetylation processes.