摘要
内切糖苷酶F／N-糖苷酶F可使Alzheimer病神经原纤维缠结选择性去糖基化。去糖基化作用使神经原纤维缠结的螺旋消失，在电子显微镜下呈直径为（2．5±0．5）nm的线性纤维丝结构，这些线性纤维丝常以束存在。单纯去糖基化作用并不引起tau蛋白从缠结结构的释放量明显增高，但去糖基化处理可明显增高蛋自磷酸酯酶从缠结结构中释放游离tau蛋白。这些结果揭示，tau蛋白的糖基化作用与Alzheimer病患者脑中神经原纤维缠结结构的稳定性有关。
Tau in Alzheimer neurofibrillary tangles is abnormally glycosylated. Deglycosylation of Paired helical filament (PHF)by endoglycosidase F/N-glycosidase F converts them into bundles of straight Filaments(2.5±0.5)nm in diameter similar to those generated by the interaction of normal tau and abnormally hyperphosphorylated tau. Deglycosylation plus dephosphorylation, but not deglycosylation alone, of PHF tangles reults in increased tau release. Thus, although the abnormal phosphorylation might promote Aggregation of tau and inhibition of the assembly of microtubules, glycosylation appears to be responsible for The maintenance of the PHF structure.
