应用磁金纳米粒子研究牛血清白蛋白与牛蒡子苷之间的相互作用

Application of Magnetic Gold Nanoparticles for Interaction between Bovine Serum Albumin and Arctiin

建立了用于确定血清白蛋白与中药有效成分相互作用结合常数和结合位点数的新方法。利用磁金纳米粒子的超顺磁性和生物相容性,将其作为白蛋白的载体。将牛血清白蛋白固定在磁金纳米粒子上,白蛋白与药物结合后,通过外加磁场将磁金纳米粒子-白蛋白-药物复合物与游离药物分离,通过荧光光谱法得到的游离药物浓度,根据Scatchard方程直接计算出白蛋白与药物的结合常数和结合位点数。本方法用于研究牛血清白蛋白和牛蒡子苷之间的相互作用,结合常数为2.09×105L/mol,结合位点数为16.63。通过外加磁场作用,使白蛋白从样品溶液中分离出来,样品溶液中只有药物,消除了测定药物时白蛋白的影响,因此所求得的结合位点的数目更准确。实验结果表明,本方法可用于测定分子间非共价结合的结合常数和结合位点数,同时为研究中药有效成分与血清白蛋白相互作用提供了参考。

A new method was developed for determining the binding constant and number of binding site of protein with drug. With superparamagnetic and biocompatible characteristics,magnetic gold nanoparticles could be used as the carrier for proteins. The magnetic gold nanoparticles were used for fixing protein. After the binding of protein with drug,the magnetic gold nanoparticles-protein-drug complex was separated from the free drug with applied magnetic field. The free drug concentration was obtained directly by fluorescence spectrometry. The binding constant and binding sites were calculated with Scatchard equation. This method was suitable for studying the interaction between arctiin and bovine serum albumin（ BSA）. BSA and arctiin binding constants and binding sites were 2. 09 × 10^5 L / mol and 16. 63,respectively. BSA could be separated from the sample solution in the magnetic field. As a result,there are only drugs in the sample solution and the protein could not affect the drugs determination. So the number of binding sites should be reliable. The results confirmed that the method was suitable to the measurement of the binding constant and the number of binding sites of molecular interactions. And this new method could be used to study the interactions of serum albumin with the active ingredients of Chinese medicine.