The research on arylamine N-acetytransferase derived from brain

芳香胺N-乙酰转移酶（NAT）主要来源于肝脏，对外界芳香胺进行解毒。脑源性NAT具有较高的活性，并有可能对可能使中枢神经系统变性的外源性芳胺和内源性芳胺类似物进行解毒。然而，脑源性NAT的功能尚不清楚。为了阐明脑源性NAT的功能，我们尝试用原位PCR方法研究NAT在大鼠脑组织中的分布，发现NAT mRNA在神经元胞质和核内均有表达。我们无法确定信号是否来自基因组DNA。接下来，我们尝试在大鼠脑中进行原位杂交。从单态性和多态性NAT cDNA的同源性较低的区域中选择了几种反义探针，在神经元和室管膜细胞层显示了NAT mRNA的信号。在未来，我们希望调查多态NAT在大脑中的分布，特别是从体液的大门区域。在大肠杆菌中表达人多态性和单态性NAT，并使用组氨酸标签进行修饰。这些酶用于确定NAT是否在犬尿氨酸途径中起任何作用。在众多的候选药物中，我们选择犬尿氨酸并合成了N ′-乙酰基-L-犬尿氨酸作为标准品。然而，NAT不代谢犬尿氨酸。最后探讨了NAT对中枢神经系统的影响。阿尔茨海默病是一种与衰老有关的神经退行性疾病。我们检测了阿尔茨海默病患者和正常人的NAT 2（多态性）分型。他们发现AD患者中NAT 2的分布与对照受试者中观察到的分布没有显着差异。然而，他们认为非载脂蛋白E β 4携带者中的快速乙酰化可能是危险因素。

Arylamine N-acetyltransferase (NAT) is mainly originated from liver that detoxify external arylamine. Brain derived NAT is rather high activity and has the possibility to detoxify external arylamine and endogenous arylamine analogues that might denature central nervous system. However the function of brain derived NAT is unknown. To clarify the function of brain derived NAT,we tried to find the distribution of NAT in ratbrain by in situ PCR.The signal from NAT mRNA was observed in both cytoplasm and nuclear of neuron. We could not determine whether the signal came from genomic DNA or not. Next we tried in situ hybridization in rat brain. Several kinds of antisence probes were chosen from comparative low homology region of monomorphic and polymorphic NAT cDNA.The signal from NAT mRNA was shown in neuron and ependymal cell layr. In the future we want to investigate the distribution of polymorphic NAT in the brain, in particular the region that is the gate from body fluid. Human polymorphic and monomorphic NAT were expressed in E.coli and were **rified in use of histidine tag. These enzymes were used to determine whether NAT playd any role in kynurenine pathway. Among of many candidates, we chose kynurenine and synthesized N'-acetyI-L-kynurenine as a standard. However NAT didn't metabolize kynurenine. Finally we investigated the effect of NAT on central nervous system. AIzheimer's disease is one of aging-related neurodegenerative disorders. We determined the typing of NAT2 (polymorphic) in AIzheimer's disease patient combined with normal people. They revealed that the distributions of NAT2 in AD patients were not significantly different from those observed in control subjects. However, they have suggested that rapid acetylator in the group of non-apolipoprotein E epsilon 4 carrier might be risk factors.