Unexpected Acetylation of Endogenous Aliphatic Amines by Arylamine N‐Acetyltransferase NAT2

Abstract

N‐Acetyltransferases play critical roles in the deactivation and clearance of xenobiotics, including clinical drugs. NAT2 has been classified as an arylamine N‐acetyltransferase that mainly converts aromatic amines, hydroxylamines, and hydrazines. Herein, we demonstrate that the human arylamine N‐acetyltransferase NAT2 also acetylates aliphatic endogenous amines. Metabolomic analysis and chemical synthesis revealed increased intracellular concentrations of mono‐ and diacetylated spermidine in human cell lines expressing the rapid compared to the slow acetylator NAT2 phenotype. The regioselective N8‐acetylation of monoacetylated spermidine by NAT2 answers the long‐standing question of the source of diacetylspermidine. We also identified selective acetylation of structurally diverse alkylamine‐containing drugs by NAT2, which may contribute to variations in patient responses. The results demonstrate a previously unknown functionality and potential regulatory role for NAT2, and we suggest that this enzyme should be considered for re‐classification.

Differential regulation of oxidative stress, microbiota-derived, and energy metabolites in the mouse brain during sleep

“…Metabolites from each biological replica of every examined brain region were extracted separately following standard procedures and spiking of an isotopically labelled internal standard. 19,20 The samples were analyzed by UPLC-MS/MS with a randomized sample sequence in negative and positive ionization mode. The volume during reconstitution was adjusted to the weight of each brain region and the samples were analyzed by UPLC-MS/MS (Supplementary Table 1).…”

Drug metabolism in the lungs: opportunities for optimising inhaled medicines

“…Nevertheless, GST activity is relatively high compared to other drug metabolizing enzymes within the lungs and based on enzyme activity studies is likely to contribute significantly to phase II metabolism in the lungs, along with NAT [15,23]. NAT1 and to a lesser extent NAT2 activity has been shown in the lungs with most research focused on either the metabolism of endogenous molecules, or inhaled toxicants along with genetic polymorphisms and the implications of this for cancer [24][25][26]. SULT activity in primary lung parenchymal cells has been explored to a greater extent, and depending on the substrate appears to be both significant and comparable to that of human hepatocytes [17].…”

Arylamine N-acetyltransferase acetylation polymorphisms: paradigm for pharmacogenomic-guided therapy- a focused review

“…Some of them (such as clonazepam) are metabolized to an aromatic amine metabolite which is then subject to NAT2 genetic polymorphism [79]. A recent new study [80] provides data suggesting that NAT2 substrate specificity may also extend to drugs with aliphatic amine functional groups. Using cell-based and in vitro assays, they report acetylation of several endogenous metabolites and major drugs that have not previously been described as substrates for NAT2.…”

“…Using cell-based and in vitro assays, they report acetylation of several endogenous metabolites and major drugs that have not previously been described as substrates for NAT2. The study [80] investigated eight representative drugs possessing aliphatic amines to determine whether they are acetylated by NAT2. The calcium channel blocker amlodipine, the serotonin-norepinephrine inhibitor duloxetine, the beta blockers nebivolol and carvedilol were found to be N-acetylated by NAT2.…”

“…The calcium channel blocker amlodipine, the serotonin-norepinephrine inhibitor duloxetine, the beta blockers nebivolol and carvedilol were found to be N-acetylated by NAT2. These drugs are used to treat and prevent prevalent conditions such as hypertension, stroke, fibromyalgia, anxiety, and depression and over 20% of the 200 most prescribed drugs in the USA contain aliphatic amines, representing almost 900 million prescriptions [80]. This is a new and unconfirmed report which did not assess the effects of acetylator phenotype on metabolism, efficacy, or toxicity.…”