电喷雾离子阱质谱法研究射干苷与血浆蛋白的非共价结合

Non-covalent binding between tectoridin and plasma proteins by electrospray ion trap mass spectrometry

目的研究射干苷与血浆蛋白的非共价结合特性。方法采用电喷雾离子阱质谱分别测定射干苷、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的变化计算复合物最大化学计量比;通过Scatchard方程拟合计算复合物结合常数K;根据反应温度和热力学常数△H、△S推测复合物间的作用力类型。结果射干苷与人血清白蛋白、α1-酸性糖蛋白形成的非共价复合物K分别为1.914×104mol/L和5.893×104mol/L,结合倍数分别为7.8和3.3复合物间的作用力主要为静电引力。结论电喷雾离子阱质谱法应用于射干苷与蛋白质结合的研究具有灵敏度高、特异性强、分析迅速等优点。

Objective To study the non-covalent binding between the tectoridin （TE） and plasma proteins. Methods The molecular weights of TE, human serum albumin （HSA）, α1-acid glycoprotein （AAG） and the protein-drug complexes were measured by the electrospray ion trap 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 （K） 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 （△H and △S）. Results The K of the complexes were 1. 914 ×10^4 mol/L for TE-HSA and 5. 893 ×10^4 mol/L for TEAAG, and the number of binding sites were 7.8 and 3.3, respectively. The main sorts of binding force between TE-HSA or TE-AAG were static-electricity gravitation. Conclusion ESI-MS is a good method for studying of the TE-protein non-covalent binding with some advantages in sensitivity, high-speed, and accuracy.