Liu W K, Ksiezak-Reding H, Yen S H
Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461.
J Biol Chem. 1991 Nov 15;266(32):21723-7.
Abnormal tau proteins (PHF-tau) were isolated from Alzheimer's disease brains by treatment of paired helical filament enriched-fractions with perchloric acid and boiling of the acid precipitable fraction with beta-mercaptoethanol. These proteins were purified further by a second perchloric acid treatment. The purified PHF-tau proteins were soluble in buffers devoid of sodium dodecyl sulfate. However, they were similar to the abnormal tau extracted from paired helical filaments with sodium dodecyl sulfate, also named A68, in molecular mass (68, 64, and 60 kDa), isoelectric point (pI 5.5-6.5), reactivity with anti-tau antibodies, and in requirement for alkaline phosphatase treatment to bind the Tau-1 antibody. Compared to normal tau, the soluble PHF-tau contained 100% more glycine and 35% less lysine residue. The results suggest that besides phosphorylation other types of modification may be involved in differentiating PHF-tau from normal tau.
通过用高氯酸处理富含双螺旋丝的组分，并将酸沉淀部分与β-巯基乙醇一起煮沸，从阿尔茨海默病大脑中分离出异常tau蛋白（PHF-tau）。这些蛋白通过第二次高氯酸处理进一步纯化。纯化后的PHF-tau蛋白可溶于不含十二烷基硫酸钠的缓冲液中。然而，它们在分子量（68、64和60 kDa）、等电点（pI 5.5 - 6.5）、与抗tau抗体的反应性以及结合Tau-1抗体所需的碱性磷酸酶处理方面，与用十二烷基硫酸钠从双螺旋丝中提取的异常tau（也称为A68）相似。与正常tau相比，可溶性PHF-tau的甘氨酸含量多100%，赖氨酸残基含量少35%。结果表明，除了磷酸化外，其他类型的修饰可能也参与了PHF-tau与正常tau的区分。
