Krishnan Anandi, Sturgeon Jacqueline, Siedlecki Christopher A, Vogler Erwin A
Department of Bioengineering, University Park, Pennsylvania 16802, USA.
J Biomed Mater Res A. 2004 Mar 1;68(3):544-57. doi: 10.1002/jbm.a.20104.
A principal conclusion drawn from observations of time- and concentration-dependent liquid-vapor (LV) interfacial tension gamma(lv) of a diverse selection of proteins ranging from albumin to ubiquitin spanning nearly three decades in molecular weight (MW) is that concentration scaling substantially alters perception of protein interfacial activity as measured by reduction in gamma(lv). Proteins appear more similar than dissimilar on a weight/volume basis, whereas molarity scaling reveals a "Traube-rule" ordering by MW, suggesting that adsorption is substantially driven by solution concentration rather than diversity in protein amphilicity. Scaling as a ratio-to-physiological-concentration demonstrates that certain proteins exhibit the full possible range of interfacial activity at and well-below physiological concentration, whereas others are only weakly surface active within this range, requiring substantially higher solution concentration to achieve reduction in gamma(lv). Important among this latter category of proteins are the blood factors XII and XIIa, assumed by the classical biochemical mechanism of plasma coagulation to adsorb to procoagulant surfaces, even in the presence of overwhelming concentrations of other blood constituents such as albumin and immunoglobulin that are shown by this work to be among the class of highly surface-active proteins at physiologic concentration. A comparison of pendant drop and Wilhelmy balance tensiometry as tools for assessing protein interfacial activity shows that measurement conditions employed in the typical Wilhelmy plate approach fails to achieve the steady-state adsorption condition that is accessible to pendant drop tensiometry.
从对一系列蛋白质（从白蛋白到泛素，分子量跨度近三十年）的时间和浓度依赖性液 - 气（LV）界面张力γ(lv)的观察中得出的一个主要结论是，浓度缩放显著改变了通过γ(lv)降低来衡量的蛋白质界面活性的认知。基于重量/体积，蛋白质看起来相似而非不同，而摩尔浓度缩放则揭示了按分子量的“特劳贝规则”排序，这表明吸附主要由溶液浓度驱动，而非蛋白质两亲性的多样性。以与生理浓度的比值进行缩放表明，某些蛋白质在生理浓度及远低于生理浓度时展现出完整的界面活性范围，而其他蛋白质在此范围内仅具有较弱的表面活性，需要实质上更高的溶液浓度才能实现γ(lv)的降低。后一类蛋白质中重要的是血液因子XII和XIIa，根据血浆凝血的经典生化机制，它们即使在存在大量其他血液成分（如白蛋白和免疫球蛋白，本研究表明这些成分在生理浓度下属于高表面活性蛋白质类别）的情况下，也会吸附到促凝表面。对悬滴法和威尔海姆平板张力测定法作为评估蛋白质界面活性工具的比较表明，典型威尔海姆平板方法中采用的测量条件无法达到悬滴张力测定法可实现的稳态吸附条件。
