transacetylase

Transacetylase is a term used for enzymes that catalyze the transfer of an acetyl group from an acetyl donor to an acceptor molecule. It is part of the broader acetyltransferase family and, in many cases, uses acetyl-CoA as the acetyl donor with CoA released as a byproduct. Some transacetylases can operate with alternative donors or transfer acetyl groups between other substrates, depending on the enzyme and cellular context.

Biological roles of transacetylases are diverse. In bacteria, they can modify cell wall components, such as O-acetyltransferases that acetylate specific positions on peptidoglycan and contribute to structural integrity or resistance to lysozyme. In animals and humans, arylamine N-acetyltransferases (NAT1 and NAT2) participate in the detoxification and metabolism of arylamines and hydrazines, and genetic variation in these enzymes can influence drug response and cancer risk. In plants and microbes, transacetylases participate in the biosynthesis of acetylated secondary metabolites and other specialized compounds.

Classification and mechanism are variable across families. Most transacetylases are categorized within EC 2.3.x.x (acyltransferases). A major and well-studied subclass is the GNAT (Gcn5-related N-acetyltransferase) family, which transfers acetyl groups from acetyl-CoA to amine or other nucleophilic acceptors. Reactions may proceed via direct transfer or through transient enzyme-bound acetyl intermediates, depending on the specific enzyme.

Structure and distribution vary; transacetylases can be soluble cytosolic enzymes or membrane-associated proteins, and catalytic motifs around the acetyl-CoA binding site are common features used for identification. They are studied for roles in antibiotic resistance, drug metabolism, and biosynthetic pathways, with implications for pharmacology and microbial physiology.