摘要
在模拟生理条件下,采用荧光猝灭光谱、三维荧光光谱、紫外可见吸收光谱及圆二色谱法首次研究了盐酸克伦特罗(Clenbuterol hydrochloride,CL)与人免疫球蛋白G(Human immunoglobulin G,HIgG)之间的相互作用。根据Scatchard方程和Vant Hoff方程计算了不同温度下CL和HIgG的结合常数和热力学常数。荧光猝灭实验结果表明CL可以使HIgG发生荧光猝灭。在298、304、310 K温度下,CL与HIgG间的结合常数分别为2.95×104、2.35×104、1.82×104L/mol,结合位点数分别为0.84、0.87和0.94,表明两者之间的猝灭机理为静态猝灭。在CL与HIgG相互作用的体系中,其焓变和熵变的值分别为-30.47 kJ/mol和-16.58 J·K·mol-1,表明其结合过程可能同时存在几种作用力,主要为氢键和范德华力。通过三维荧光光谱和紫外光谱数据可知:CL的加入会引起HIgG二级结构的变化。此外,当HIgG与CL间的摩尔比为1∶4时,CL的加入可引起HIgGβ-折叠结构含量的减小。
Interaction of clenbuterol hydrochloride （CL） with human immunoglobulin G （HIgG） was studied using fluorescence quenching spectroscopy,three-dimensional fluorescence spectroscopy,UV-vis absorption spectroscopy and circular dichroism （CD） spectroscopy under simulative physiological conditions for the first time.The binding parameters and the thermodynamic parameters for the reaction of CL with HIgG at different temperatures were calculated according to Scatchard equation and Van＇t Hoff equation,respectively.Experimental results of the fluorescence quenching spectra showed that the fluorescence intensity of HIgG was quenched by the gradual addition of CL.The binding constants of CL with HIgG at 298,304,310 K were calculated to be 2.95 × 104,2.35 × 104,1.82 ×104 L/mol,respectively,meaning that the quenching mechanism was a static quenching.Meanwhile,the corresponding numbers of binding sites （n） were calculated to be 0.84,0.87 and 0.94,respectively.The thermodynamic parameters of the reaction,namely standard enthalpy AH0 and entropy △S0,were calculated to be-30.47 kJ · mol-1 and-16.58 J · K · mol-1,respectively,suggesting that there were several forces in the binding of CL with HIgG,and the hydrogen bond and Vander Waals force were the predominant intermolecular forces in stabilizing the CL-HIgG complex.Experimental results obtained from the three-dimensional fluorescence spectroscopy and UV-vis absorption spectroscopy confirmed that the secondary structure of HIgG was altered in the presence of CL in aqueous solution.Furthermore,a decrease of the β-structure compositions of HIgG was observed by CD spectroscopy when the molar concentration ratio of HIgG to CL was 1 ∶ 4.
出处
《分析测试学报》
CAS
CSCD
北大核心
2013年第10期1197-1201,共5页
Journal of Instrumental Analysis
基金
陕西理工学院校级人才启动项目(SLGQD13-3)
关键词
盐酸克伦特罗
人免疫球蛋白G
光谱法
相互作用
clenbuterol hydrochloride
human immunoglobulin G
spectroscopy
interaction
