N-acetyltransferase (NAT) is an enzyme that catalyzes the transfer of acetyl groups from acetyl-CoA to arylamines, arylhydroxylamines and arylhydrazines.

N-acetyltransferases are cytosolic enzymes found in the liver and many tissues of most mammalian species, except the dog and fox, which cannot acetylate xenobiotics.

[4] Acetyl groups are important in the conjugation of metabolites from the liver, to allow excretion of the byproducts (phase II metabolism).

NAT enzymes are differentiated by the presence of a conserved catalytic triad that favors aromatic amine and hydrazine substrates.

[9][10] Further, all functional NAT enzymes contain a triad of catalytically essential residues made up of this cysteine, histidine, and asparagine.

[4] Human NAT2 preferentially acetylates isoniazid (treatment for tuberculosis), hydralazine, procainamide, dapsone, aminoglutethimide, and sulfamethazine.

[17] Beyond modifying enzymatic activity, epidemiological studies have found an association of NAT2 polymorphisms with various cancers, likely from varying environmental carcinogens.

[19] Single nucleotide polymorphisms (SNPs) of NAT1 include R64W, V149I, R187Q, M205V, S214A, D251V, E26K, and I263V, and are related to genetic predisposition to cancer, birth defects, and other diseases.

[20] The effect of the slow acetylator SNPs in the coding region predominantly act through creating an unstable protein that aggregates intracellularly prior to ubiquitination and degradation.