Metabolic activation of aromatic and heterocyclic N-hydroxyarylamines by wild-type and mutant recombinant human NAT1 and NAT2 acetyltransferases

Arch Toxicol. 1994;68(2):129-33. doi: 10.1007/s002040050045.


Recombinant human NAT1 and polymorphic NAT2 wild-type and mutant N-acetyltransferases (encoded by NAT2 alleles with mutations at 282/857, 191, 282/590, 341/803, 341/481/803, and 341/481) were expressed in Escherichia coli strains XA90 and/or JM105, and tested for their capacity to catalyze the metabolic activation (via O-acetylation) of the N-hydroxy (N-OH) derivatives of 2-aminofluorene (AF), and the heterocyclic arylamine mutagens 2-amino-3-methylimidazo [4,5-f]quinoline (IQ), 2-amino-3,4-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Both NAT1 and NAT2 (including all mutant human NAT2s tested) catalyzed the metabolic activation of each of the N-hydroxyarylamines to products that bound to DNA. Metabolic activation of N-OH-AF was greater than that of the heterocyclic N-hydroxyarylamines. The relative capacity of NAT1 versus NAT2 to catalyze activation varied with N-hydroxyarylamine substrate. N-OH-MeIQx and N-OH-PhIP exhibited a relative specificity for NAT2. These results provide mechanistic support for a role of the genetic acetylation polymorphism in the metabolic activation of heterocyclic amine mutagens and carcinogens.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylation
  • Acetyltransferases / metabolism*
  • Acyltransferases / metabolism
  • Amines / metabolism
  • Arylamine N-Acetyltransferase / metabolism*
  • Base Sequence
  • Biotransformation
  • Blotting, Western
  • Heterocyclic Compounds / metabolism
  • Humans
  • Hydroxylamines / metabolism*
  • Hydroxylamines / pharmacokinetics
  • Molecular Sequence Data
  • Polymorphism, Genetic
  • Recombinant Proteins / metabolism
  • Substrate Specificity


  • Amines
  • Heterocyclic Compounds
  • Hydroxylamines
  • Recombinant Proteins
  • Acyltransferases
  • Acetyltransferases
  • protein N-terminal acetyltransferase
  • N-hydroxyarylamine O-acetyltransferase
  • Arylamine N-Acetyltransferase
  • NAT2 protein, human