Institut des Sciences Analytiques, UMR 5280, Université de Lyon, CNRS, Université Claude Bernard Lyon 1, 25 rue Becquerel, 69100, Villeurbanne, France.
Anal Bioanal Chem. 2022 Jul;414(18):5347-5355. doi: 10.1007/s00216-021-03769-8. Epub 2021 Nov 23.
Although the interaction between the β-amyloid peptide and copper (II) appears to play an important role in Alzheimer's disease, the affinity constant is still controversial and values are ranging from 10 to 10 M. With the aim of clarifying this point, a complementary method, based on the capillary electrophoresis-ICP-MS hyphenation, was developed and competitive binding experiments were conducted in the presence of nitrilotriacetic acid. The effect of the capillary surface (neutral or positively charged) and nature of the buffer (Tris or Hepes) have been studied. Tris buffer was found to be inappropriate for such determination as it enhances the dissociation of copper (II) complexes, already occurring in the presence of an electric field in capillary electrophoresis. Using Hepes, a value of 10 M was found for the affinity of the small β-amyloid peptide 1-16 for copper (II), which is in agreement with the values obtained for other proteins involved in neurodegenerative diseases. These constants were also determined in conditions closer to those of biological media (higher ionic strength, presence of carbonates).
虽然 β-淀粉样肽与铜（II）之间的相互作用似乎在阿尔茨海默病中起着重要作用，但亲和常数仍存在争议，其值范围为 10 到 10 M。为了澄清这一点，开发了一种基于毛细管电泳-ICP-MS 联用的补充方法，并在氮三乙酸存在下进行了竞争性结合实验。研究了毛细管表面（中性或带正电荷）和缓冲液性质（Tris 或 Hepes）的影响。发现 Tris 缓冲液不适合这种测定，因为它会增强铜（II）配合物的解离，而这些配合物已经在毛细管电泳中存在电场的情况下发生解离。使用 Hepes，发现小 β-淀粉样肽 1-16 与铜（II）的亲和常数为 10 M，这与其他涉及神经退行性疾病的蛋白质的测定值一致。这些常数也在更接近生物介质条件（更高的离子强度，存在碳酸盐）下进行了测定。
