transacetylation

Transacetylation is a chemical and biochemical process in which an acetyl group (CH3CO–) is transferred from one molecule (the donor) to another (the acceptor). It is a subset of acyl transfer reactions and can occur through enzymatic catalysis or non-enzymatic chemical routes. In biology, acetyl groups are commonly donated from acetyl-CoA, with the group transferred to amine, hydroxyl, or thiol sites on enzymes, metabolites, or antibiotics.

Enzymatic transacetylation is typically mediated by acetyltransferases, including N-acetyltransferases and O-acetyltransferases. These enzymes often use acetyl-CoA as the donor and achieve the transfer via a catalytic mechanism that forms an acetyl-enzyme intermediate or directly transfers the acetyl group to the acceptor. Biological transacetylation plays roles in protein regulation, metabolism, and antibiotic resistance, among other processes.

In antibiotic resistance, bacteria can acquire transacetylation activity through acetyltransferases that modify aminoglycoside antibiotics, reducing their effectiveness. In cellular regulation, protein acetylation by transacetylation can modulate activity, stability, or interactions of target proteins. Transacetylation is also relevant in carbohydrate and lipid metabolism, where acetyl groups are redistributed to or from various metabolites.

Non-enzymatic transacetylation can occur in chemical synthesis or during workup with acetylating agents such as acetic anhydride or acetyl chloride, and is used in organic synthesis for protection-deprotection strategies or the preparation of acetylated derivatives.

See also: acetyltransferase, acetyl donor, acyl transfer reactions.