Näslund J, Karlström A R, Tjernberg L O, Schierhorn A, Terenius L, Nordstedt C
Department of Clinical Neuroscience, Karolinska Hospital, Stockholm, Sweden.
J Neurochem. 1996 Jul;67(1):294-301. doi: 10.1046/j.1471-4159.1996.67010294.x.
In Alzheimer's disease (AD), one of the cardinal neuropathological signs is deposition of amyloid, primarily consisting of the amyloid beta-peptide (Abeta). Structural variants of AD-associated Abeta peptides have been difficult to purify by high-resolution chromatographic techniques. We therefore developed a novel chromatographic protocol, enabling high-resolution reverse-phase liquid chromatography (RPLC) purification of Abeta variants displaying very small structural differences. By using a combination of size-exclusion chromatography and the novel RPLC protocol, Abeta peptides extracted from AD amyloid were purified and subsequently characterized. Structural analysis by microsequencing and electrospray-ionization mass spectrometry revealed that the RPLC system resolved a complex mixture of Abeta variants terminating at either residue 40 or 42. Abeta variants differing by as little as one amino acid residue could be purified rapidly to apparent homogeneity. The resolution of the system was further illustrated by its ability to separate the structural isomers of Abeta1-40. The present chromatography system might provide further insight into the role of N-terminally and posttranslationally modified Abeta variants, because each variant can now be studied individually.
在阿尔茨海默病（AD）中，主要由β淀粉样肽（Aβ）构成的淀粉样蛋白沉积是主要的神经病理学特征之一。与AD相关的Aβ肽的结构变体一直难以通过高分辨率色谱技术进行纯化。因此，我们开发了一种新颖的色谱方法，能够通过高分辨率反相液相色谱（RPLC）纯化具有极小结构差异的Aβ变体。通过结合尺寸排阻色谱法和新颖的RPLC方法，从AD淀粉样蛋白中提取的Aβ肽得以纯化并随后进行表征。通过微量测序和电喷雾电离质谱进行的结构分析表明，RPLC系统能够分离以第40位或第42位残基结尾的复杂Aβ变体混合物。仅相差一个氨基酸残基的Aβ变体能够迅速纯化至表观均一性。该系统的分辨率还通过其分离Aβ1-40结构异构体的能力得到进一步说明。由于现在可以单独研究每个变体，当前的色谱系统可能会为N端和翻译后修饰的Aβ变体的作用提供进一步的见解。
