Arylamine N-acetyltransferase I

Arylamine N-acetyltransferase I (NAT1) is a phase II enzyme that acetylates a wide range of arylamine and hydrazine substrates. The NAT1 gene is located on chromosome 8 and shares homology to NAT genes found in most mammalian species. Gene expression occurs from at least two promoters and a number of tissue-specific transcripts have been identified. The gene is polymorphic with most mutations identified to date producing an unstable protein that is subject to polyubiquitination. The NAT1 protein contains a catalytic triad similar to a number of cysteine proteases and transglutaminases. NAT1 is widely distributed in the body, but the only endogenous substrate identified to date is the folate catabolite p-aminobenzoylglutamate. Recent links between NAT1 genotypes and susceptibility to spina bifida suggests that the enzyme has an important role in folate homeostasis.