Delahaije Roy J B M, Gruppen Harry, Giuseppin Marco L F, Wierenga Peter A
Laboratory of Food Chemistry, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
AVEBE, Prins Hendrikplein 20, 9641 GK Veendam, The Netherlands.
Colloids Surf B Biointerfaces. 2014 Nov 1;123:199-206. doi: 10.1016/j.colsurfb.2014.09.015. Epub 2014 Sep 28.
The adsorption behaviour of proteins depends significantly on their molecular properties and system conditions. To study this relation, the effect of relative exposed hydrophobicity, protein concentration and ionic strength on the adsorption rate and adsorbed amount is studied using β-lactoglobulin, ovalbumin and lysozyme. The curves of surface elastic modulus versus surface pressure of all three proteins, under different conditions (i.e. concentration and ionic strength) superimposed. This showed that the interactions between the adsorbed proteins are similar and that the adsorbed proteins retain their native state. In addition, the adsorption rate (kadsorb) was shown to scale with the relative hydrophobicity and ionic strength. Moreover, the adsorbed amount was shown to be dependent on the protein charge and the ionic strength. Based on these results, a model is proposed to predict the maximum adsorbed amount (Γmax). The model approximates the adsorbed amount as a close-packed monolayer using a hard-sphere approximation with an effective protein radius which depends on the electrostatic repulsion. The theoretical adsorbed amount was in agreement with experimental Γmax (±10%).
蛋白质的吸附行为很大程度上取决于其分子特性和系统条件。为研究这种关系，使用β-乳球蛋白、卵清蛋白和溶菌酶研究了相对暴露疏水性、蛋白质浓度和离子强度对吸附速率和吸附量的影响。在不同条件（即浓度和离子强度）下，所有三种蛋白质的表面弹性模量与表面压力的曲线相互叠加。这表明吸附蛋白质之间的相互作用相似，且吸附的蛋白质保持其天然状态。此外，吸附速率（kadsorb）与相对疏水性和离子强度呈比例关系。而且，吸附量显示取决于蛋白质电荷和离子强度。基于这些结果，提出了一个模型来预测最大吸附量（Γmax）。该模型使用硬球近似法将吸附量近似为紧密堆积的单分子层，有效蛋白质半径取决于静电排斥力。理论吸附量与实验得到的Γmax相符（±10%）。
