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.

中文翻译：

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芳胺 N-乙酰转移酶 NAT2 对内源脂肪胺进行意外乙酰化。

N-乙酰基转移酶在异生物质（包括临床药物）的失活和清除中发挥着关键作用。NAT2被归类为芳胺N-乙酰转移酶，主要转化芳香胺、羟胺和肼。在此，我们证明人芳胺N-乙酰转移酶 NAT2 也乙酰化脂肪族内源胺。代谢组学分析和化学合成表明，与慢速乙酰化NAT2表型相比，表达快速乙酰化剂NAT2表型的人类细胞系中单乙酰化亚精胺和二乙酰化亚精胺的细胞内浓度增加。NAT2 对单乙酰化亚精胺的区域选择性N ⁸乙酰化回答了二乙酰亚精胺来源这一长期存在的问题。我们还发现了 NAT2 对结构多样的含烷基胺药物的选择性乙酰化，这可能会导致患者反应的变化。结果表明 NAT2 具有以前未知的功能和潜在的调节作用，我们建议应考虑对该酶进行重新分类。