阿尔茨海默症(Alzheimer'sdisease,AD)病人体内有两大重要的病理特征：胞外的由β淀粉样蛋白(β-amyloid,Aβ)沉积形成的淀粉样斑和胞内的由超磷酸化的tau蛋白形成的神经纤维缠结。目前AD的发病假说中最广为认可的是β淀粉样蛋白级联假说，该假说认为体内Aβ的过量积累和Aβ42/Aβ40比例的增加是导致AD发病的关键因素。Aβ的产生是由其前体蛋白APP(amyloidprecursorprotein)经β和γ分泌酶切割产生。γ分泌酶复合体主要由早老素(presenilin,PS)，APH1,PEN2,nicastrin四种组分构成，这四种组分便可以形成有活性的γ分泌酶复合体...Alzheimer's disease (AD) is characterized by β-amyloid plaques consisting of β-amyloid (Aβ) peptides and neurofibrillary tangles consisting of hyperphosphorylated tau protein. Currently the most widely accepted view about the pathogenesis of AD is the Aβ cascade hypothesis, which suggests that Aβ accumulation or an increased ratio of Aβ42 over Aβ40 play an important role in AD pathogenesis. Aβ is ...学位：理学硕士院系专业：生命科学学院生物化学与生物技术系_生物化学与分子生物学学号：2172006115224
