The research on arylamine N-acetytransferase derived from brain

芳胺n -乙酰转移酶（NAT）主要来源于肝脏，具有解毒外源芳胺的作用。脑源性NAT具有相当高的活性，有可能解毒可能变性中枢神经系统的外源性芳胺和内源性芳胺类似物。然而，脑源性NAT的功能尚不清楚。为了明确脑源性NAT的功能，我们尝试用原位PCR方法寻找NAT在大鼠脑中的分布。在神经元细胞质和细胞核中均可见到NAT mRNA的信号。我们无法确定信号是否来自基因组DNA。接下来我们尝试了大鼠脑原位杂交。从NAT cDNA单态和多态同源性较低的区域中选择了几种反义探针。NAT mRNA的信号在神经元和室管膜细胞层均可见。在未来，我们希望研究多态NAT在大脑中的分布，特别是在作为体液通道的区域。在大肠杆菌中分别表达了人多态和单态NAT，并利用组氨酸标签进行了纯化。这些酶被用来确定NAT是否在犬尿氨酸途径中起作用。在众多候选物中，我们选择了犬尿氨酸，并合成了N'-乙酰- l -犬尿氨酸作为标准。但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。我们测定了阿尔茨海默病患者与正常人的NAT2（多态性）分型。他们发现，AD患者中NAT2的分布与对照组没有显著差异。然而，他们认为非载脂蛋白E - epsilon 4携带者组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.