Kondo A, Oku S, Higashitani K
Applied Chemistry Department, Kyushu Institute of Technology, Sensuicho, Tobata, Kitakyushu 804, Japan.
Biotechnol Bioeng. 1991 Mar 15;37(6):537-43. doi: 10.1002/bit.260370607.
The effect of surface properties on the adsorption of bovine gamma-globulin, a model protein for antibody, was studied. Polystyrene latex (PS), hydrophilic copolymer lattices of styrene/2-hydroxyethyl methacrylate [P(S/HEMA)], styrene/ methacrylic acid [P(S/MAA)] and methyl methacrylate/ 2-hydroxyethyl methacrylate [P(MMA/HEMA)], and colloidal silica were used. The adsorption isotherms of gamma-globulin on these colloidal particles were measured as a function of pH and ionic strength. The hydrophilic particles showed low affinities for gamma-globulin at alkaline pH, while PS showed high affinities for gamma-globulin over the whole range of pH and ionic strength. The gamma-globulin adsorption on hydrophilic particles was highly reversible with respect to the pH and ionic strength compared with that on PS. These differences indicate that the dominant driving forces of adsorption are related to the hydrophilicity of particles. The adsorption isotherms of all colloidal particles showed the plateau values, and the order of maximum values of plateau adsorption was P(S/MAA) > PS or P(S/HEMA), silica > P(MMA/HEMA). Thus, they were also affected by the charged groups and the hydrophilicity of the surfaces. On the other hand, the plateau values of all colloidal particles were more or less symmetrical with a maximum at around the isoelectric point of gamma-globulin at an ionic strength of 0.01. This behavior is attributed to the important role of the lateral interaction between the adsorbed molecules at low ionic strength.
研究了表面性质对牛γ-球蛋白（一种抗体模型蛋白）吸附的影响。使用了聚苯乙烯胶乳（PS）、苯乙烯/甲基丙烯酸2-羟乙酯的亲水性共聚物胶乳[P(S/HEMA)]、苯乙烯/甲基丙烯酸[P(S/MAA)]和甲基丙烯酸甲酯/甲基丙烯酸2-羟乙酯[P(MMA/HEMA)]以及胶体二氧化硅。测量了γ-球蛋白在这些胶体颗粒上的吸附等温线随pH值和离子强度的变化。亲水性颗粒在碱性pH下对γ-球蛋白的亲和力较低，而PS在整个pH和离子强度范围内对γ-球蛋白都有较高的亲和力。与PS相比，γ-球蛋白在亲水性颗粒上的吸附相对于pH和离子强度具有高度可逆性。这些差异表明吸附的主要驱动力与颗粒的亲水性有关。所有胶体颗粒的吸附等温线都显示出平台值，平台吸附最大值的顺序为P(S/MAA)>PS或P(S/HEMA)、二氧化硅>P(MMA/HEMA)。因此，它们也受到表面带电基团和亲水性的影响。另一方面，在离子强度为0.01时，所有胶体颗粒的平台值或多或少呈对称分布，在γ-球蛋白的等电点附近出现最大值。这种行为归因于低离子强度下吸附分子间横向相互作用的重要作用。
