葛根素与血浆蛋白非共价结合的电喷雾离子阱质谱研究

 目的研究葛根素与人血清白蛋白和α₁-酸性糖蛋白之间的非共价结合特性。方法应用电喷雾离子阱质谱分别测定葛根素、人血清白蛋白、α₁-酸性糖蛋白及其所形成复合物的相对分子质量,通过结合前后的相对分子质量变化计算复合物化学计量比;通过Scatchard方程拟合计算复合物结合常数(K);根据热力学常数△H、△S推测复合物间的作用力类型。结果葛根素与人血清白蛋白、α₁-酸性糖蛋白形成的复合物的结合常数分别为7.59×10⁴和8.01×10⁴mol·L^-1,最大表观化学结合计量比分别为1∶5和1∶8。葛根素与人血清白蛋白、α₁-酸性糖蛋白间的作用力主要为静电引力。结论电喷雾离子阱质谱是一种研究药物与蛋白间非共价结合的灵敏快速和准确的方法。

Studies on Noncovalent Binding Between Puerarin and Plasma Protein by Electrospray Ion Trap Mass Spectrometry

OBJECTIVE To study the noncovalent binding between puerarin (PU) and two plasma proteins,such as human serum albumin(HSA) and α₁ -acid glycoprotein(AAG). METHODS The molecular weight of puerarin, human serum albumin,α₁-acid glycoprotein and their complexes were measured by the electrospray iontrap mass spectrometry(ESI-MS). The maximum stoichiometric ratios were obtained according to the molecular weight change of the complexes before and after binding reaction, the binding constants of the complexes were calculated by the scatchard equation. The main sorts of binding force of the complexes were deduced according to the relationship between the reaction temperature and the thermodynamic parameters . RESULTS The binding constants(K) and the maximum stoichiometric ratios were 7.59×10⁴mol·L^-1,and 1∶5 for PU-HSA,and 8.01×10⁴ mol·L^-1 and 1∶8 for PU-AAG, respectively.The main sorts of binding force of the complexes between puerarin and the two plasma proteins were static-electricity gravitation. CONCLUSION ESI-MS is a good method for studying the drug-protein noncovalent binding due to its some advantages in sensitivity, high-speed and accuracy .