From arylamine N-acetyltransferase to folate-dependent acetyl CoA hydrolase: impact of folic acid on the activity of (HUMAN)NAT1 and its homologue (MOUSE)NAT2.
Acetyl Coenzyme A-dependent N-, O- and N,O-acetylation of aromatic amines and hydrazines by arylamine N-acetyltransferases is well characterised. Here, we describe experiments demonstrating that human arylamine N-acetyltransferase Type 1 and its murine homologue (Type 2) can also catalyse the direct hydrolysis of acetyl Coenzyme A in the presence of folate. This folate-dependent activity is exclusive to these two isoforms; no acetyl Coenzyme A hydrolysis was found when murine arylamine N-acetyltransferase Type 1 or recombinant bacterial arylamine N-acetyltransferases were incubated with folate. Proton nuclear magnetic resonance spectroscopy allowed chemical modifications occurring during the catalytic reaction to be analysed in real time, revealing that the disappearance of acetyl CH3 from acetyl Coenzyme A occurred concomitantly with the appearance of a CH3 peak corresponding to that of free acetate and suggesting that folate is not acetylated during the reaction. We propose that folate is a cofactor for this reaction and suggest it as an endogenous function of this widespread enzyme. Furthermore, in silico docking of folate within the active site of human arylamine N-acetyltransferase Type 1 suggests that folate may bind at the enzyme's active site, and facilitate acetyl Coenzyme A hydrolysis. The evidence presented in this paper adds to our growing understanding of the endogenous roles of human arylamine N-acetyltransferase Type 1 and its mouse homologue and expands the catalytic repertoire of these enzymes, demonstrating that they are by no means just xenobiotic metabolising enzymes but probably also play an important role in cellular metabolism. These data, together with the characterisation of a naphthoquinone inhibitor of folate-dependent acetyl Coenzyme A hydrolysis by human arylamine N-acetyltransferase Type 1/murine arylamine N-acetyltransferase Type 2, open up a range of future avenues of exploration, both for elucidating the developmental role of these enzymes and for improving chemotherapeutic approaches to pathological conditions including estrogen receptor-positive breast cancer.
Department of Pharmacology, University of Oxford, Oxford, United Kingdom; Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
Nicola
N
Laurieri
Université Paris Diderot, Sorbonne Paris Cité, Unit of Functional and Adaptive Biology, Paris, France.
Julien
J
Dairou
Department of Pharmacology, University of Oxford, Oxford, United Kingdom; Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
James E
JE
Egleton
Consultant in Investigative Toxicology, Linlithgow, West Lothian, United Kingdom.
Lesley A
LA
Stanley
Department of Pharmacology, University of Oxford, Oxford, United Kingdom; Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
Angela J
AJ
Russell
Université Paris Diderot, Sorbonne Paris Cité, Unit of Functional and Adaptive Biology, Paris, France.
Jean-Marie
JM
Dupret
Department of Pharmacology, University of Oxford, Oxford, United Kingdom; Faculty of Science, Engineering and Computing, Kingston University, Kingston on Thames, United Kingdom.
Edith
E
Sim
Université Paris Diderot, Sorbonne Paris Cité, Unit of Functional and Adaptive Biology, Paris, France.
Fernando
F
Rodrigues-Lima
D000104:Acetyl-CoA Hydrolase / Q000378:metabolism*; D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D005492:Folic Acid / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D019906:Nuclear Magnetic Resonance, Biomolecular
D007527:Isoenzymes; D005492:Folic Acid; D000123:Acetyltransferases; C019736:N-hydroxyarylamine O-acetyltransferase; D001191:Arylamine N-Acetyltransferase; C089384:N-acetyltransferase 1; D000104:Acetyl-CoA Hydrolase