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pH AND IONIC STRENGTH DEPENDENCE OF STERIC MASS-ACTION MODEL PARAMETERS

ZHOU Ying;HU Feixiong;SUN Yan   

  • Online:2004-02-25 Published:2004-02-25

pH值和离子强度对空间质量作用模型参数的影响

周盈;胡飞雄;孙彦   

  1. 天津大学化工学院生物化工系,天津300072

Abstract: The adsorption equilibrium of bovine serum albumin (BSA) on a porous anion exchanger DEAE-Spherodex M in acetate buffer was studied by batch adsorption experiments. The steric mass action model (SMA) was used to express the adsorption isotherms. By linear chromatography experiments and the nonlinear least square fitting method, the SMA model parameters were determined. It was found that the characteristic charge and the steric factor became constant at pH values much higher than the isoelectric point of BSA, and ionic strength had a significant effect on the equilibrium constant by affecting the intensity of electrostatic interactions between BSA and the surface of the anion exchanger.

摘要: 以牛血清白蛋白(BSA)为模型蛋白质研究了pH值和离子强度对空间质量作用模型参数的影响。通过静态吸附实验确定了不同pH值和离子强度条件下BSA在阴离子交换剂DEAE-Spherodex M上的吸附平衡,利用色谱实验及非线性最小二乘法确定模型参数。研究发现,只有在pH值远大于BSA等电点时,蛋白质的特征电荷数和空间因子才为常数;离子交换平衡常数不仅是pH值的函数,也受到液相离子强度的影响。