Shin Nippon Biomedical Laboratories, Ltd. , Kainan 642-0017 , Japan.
Laboratory of Drug Metabolism and Pharmacokinetics , Showa Pharmaceutical University , Machida , Tokyo 194-0042 , Japan.
Chem Res Toxicol. 2018 Nov 19;31(11):1269-1276. doi: 10.1021/acs.chemrestox.8b00236. Epub 2018 Oct 25.
Arylamine N-acetyltransferases (NATs) are drug-metabolizing enzymes essential for the metabolism of endogenous substrates and xenobiotics, and their molecular characteristics have been extensively investigated in humans, but not in cynomolgus macaques, nonhuman primate species important for drug metabolism studies. In this study, cynomolgus NAT1 and NAT2 cDNAs were isolated from livers. NAT1 and NAT2 were characterized by molecular analyses and drug-metabolizing assays. A total of 9 transcript variants were found for cynomolgus NAT1, similar to human NAT1, and contained 1-4 exons with the coding region largely conserved with human NAT1. Genomic organization was similar between cynomolgus macaques and humans. Cynomolgus NAT1 and NAT2 amino acid sequences showed high sequence homology (95% and 89%, respectively) and showed close relationships with human NAT1 and NAT2 in a phylogenetic tree. Cynomolgus NAT2 mRNA was predominantly expressed in liver among the 10 different tissues analyzed, followed by kidney and jejunum. In contrast, cynomolgus NAT1 mRNA showed more ubiquitous expression with relatively more abundant expression in liver, kidney, and jejunum, along with testis. Metabolic assays using recombinant proteins showed that cynomolgus NAT1 and NAT2 metabolized human NAT substrates, including p-aminobenzoic acid, sulfamethazine, isoniazid, and 2-aminofluorene. Interestingly, p-aminobenzoic acid and isoniazid were largely metabolized by NAT1 and NAT2, respectively, in cynomolgus macaques and humans; sulfamethazine, a human NAT2 substrate, was metabolized by both NAT enzymes in cynomolgus macaques. These results suggest molecular and enzymatic similarities of NAT1 and NAT2 between cynomolgus macaques and humans, despite some small differences in substrate specificity of the enzymes.
芳香胺 N-乙酰基转移酶（NATs）是代谢内源性底物和外源性化合物所必需的药物代谢酶，其分子特征在人类中得到了广泛研究，但在非人类灵长类动物（用于药物代谢研究的重要物种）中尚未研究。在本研究中，从肝脏中分离出食蟹猴 NAT1 和 NAT2 cDNA。通过分子分析和药物代谢测定对 NAT1 和 NAT2 进行了表征。共发现 9 种食蟹猴 NAT1 的转录变体，与人类 NAT1 相似，包含 1-4 个外显子，编码区与人类 NAT1 大部分保守。基因组组织在食蟹猴和人类之间相似。食蟹猴 NAT1 和 NAT2 氨基酸序列显示出高度的序列同源性（分别为 95%和 89%），并在系统发育树中与人类 NAT1 和 NAT2 关系密切。在分析的 10 种不同组织中，食蟹猴 NAT2 mRNA 主要在肝脏中表达，其次是肾脏和空肠。相比之下，食蟹猴 NAT1 mRNA 表现出更广泛的表达，在肝脏、肾脏和空肠中相对更丰富，同时在睾丸中也有表达。使用重组蛋白进行的代谢测定表明，食蟹猴 NAT1 和 NAT2 代谢人类 NAT 底物，包括对氨基苯甲酸、磺胺甲噁唑、异烟肼和 2-氨基芴。有趣的是，在食蟹猴和人类中，对氨基苯甲酸和异烟肼主要由 NAT1 和 NAT2 代谢；磺胺甲噁唑，一种人类 NAT2 底物，在食蟹猴中由两种 NAT 酶代谢。这些结果表明，尽管酶的底物特异性存在一些小差异，但食蟹猴和人类的 NAT1 和 NAT2 具有分子和酶学相似性。
