Johnson G, Moore S W
Department of Medical Biochemistry, University of Stellenbosch, Tygerberg, 7505, South Africa.
Biochem Biophys Res Commun. 1999 May 19;258(3):758-62. doi: 10.1006/bbrc.1999.0705.
There is accumulating evidence that acetylcholinesterase has secondary noncholinergic functions, related to adhesion, differentiation, and the deposition of beta-amyloid in Alzheimer's disease. We have observed that the specific acetylcholinesterase peripheral anionic site inhibitors, BW284c51 and propidium iodide, abrogated cell-substrate adhesion in three human neuroblastoma cell lines. The active-site inhibitors, eserine and edrophonium, in contrast, had no effect. Certain anti-AChE antibodies were also shown to inhibit adhesion. Of these, the most effective were a monoclonal (E8) and a polyclonal having cholinesterase-like catalytic activity. These were raised against an acetylcholinesterase-inhibitor complex, implying that the epitope is associated with active-site structures. Two other monoclonal antibodies (E62A1 and E65E8) partially inhibited adhesion. The epitopes of these antibodies have been shown to overlap the peripheral anionic site of acetylcholinesterase. Competition ELISA between the monoclonal antibodies and inhibitors indicated competition between E8, E62A1, and E65E8 and the peripheral-site inhibitors BW284c51 and propidium, but not with the active-site inhibitors eserine and edrophonium. Fluorescence titration between antibodies and propidium confirmed these results. We conclude that the adhesion function of acetylcholinesterase is located at the peripheral anionic site. This has implications, not only for our understanding of neural development and its disorders, but also for the treatment of neuroblastoma, the leukemias, and Alzheimer's disease.
越来越多的证据表明，乙酰胆碱酯酶具有与黏附、分化以及阿尔茨海默病中β-淀粉样蛋白沉积相关的次要非胆碱能功能。我们观察到，特异性乙酰胆碱酯酶外周阴离子位点抑制剂BW284c51和碘化丙啶可消除三种人神经母细胞瘤细胞系中的细胞-底物黏附。相比之下，活性位点抑制剂毒扁豆碱和依酚氯铵则没有效果。某些抗乙酰胆碱酯酶抗体也被证明可抑制黏附。其中，最有效的是一种具有胆碱酯酶样催化活性的单克隆抗体（E8）和一种多克隆抗体。它们是针对乙酰胆碱酯酶-抑制剂复合物产生的，这意味着该表位与活性位点结构相关。另外两种单克隆抗体（E62A1和E65E8）部分抑制了黏附。这些抗体的表位已被证明与乙酰胆碱酯酶的外周阴离子位点重叠。单克隆抗体与抑制剂之间的竞争ELISA表明，E8、E62A1和E65E8与外周位点抑制剂BW284c51和碘化丙啶之间存在竞争，但与活性位点抑制剂毒扁豆碱和依酚氯铵不存在竞争。抗体与碘化丙啶之间的荧光滴定证实了这些结果。我们得出结论，乙酰胆碱酯酶的黏附功能位于外周阴离子位点。这不仅对我们理解神经发育及其紊乱有影响，而且对神经母细胞瘤、白血病和阿尔茨海默病的治疗也有影响。
