Center for Biomolecular Interactions Bremen, University of Bremen, Germany.
Langmuir. 2011 Aug 2;27(15):9449-57. doi: 10.1021/la201856p. Epub 2011 Jul 11.
Glutathione disulfide (GSSG; γ-GluCysGly disulfide) was used as a physiologically relevant model molecule to investigate the fundamental adsorption mechanisms of polypeptides onto α-alumina nanoparticles. Its adsorption/desorption behavior was studied by enzymatic quantification of the bound GSSG combined with zeta potential measurements of the particles. The adsorption of GSSG to alumina nanoparticles was rapid, was prevented by alkaline pH, was reversed by increasing ionic strength, and followed a nearly ideal Langmuir isotherm with a standard Gibbs adsorption energy of -34.7 kJ/mol. Molecular dynamics simulations suggest that only one of the two glutathionyl moieties contained in GSSG binds stably to the nanoparticle surface. This was confirmed experimentally by the release of GSH from the bound GSSG upon reducing its disulfide bond with dithiothreitol. Our data indicate that electrostatic interactions via the carboxylate groups of one of the two glutathionyl moieties of GSSG are predominantly responsible for the binding of GSSG to the alumina surface. The results and conclusions presented here can provide a base for further experimental and modeling studies on the interactions of biomolecules with ceramic materials.
谷胱甘肽二硫化物（GSSG；γ-谷氨酰半胱氨酸甘氨酸二硫化物）被用作一种与生理相关的模型分子，以研究多肽在α-氧化铝纳米粒子上的基本吸附机制。通过结合ζ电位测量对颗粒进行酶促定量来研究结合的 GSSG 的吸附/解吸行为。GSSG 对氧化铝纳米粒子的吸附是快速的，被碱性 pH 阻止，被增加离子强度逆转，并遵循近乎理想的 Langmuir 等温线，标准 Gibbs 吸附能为-34.7 kJ/mol。分子动力学模拟表明，GSSG 中仅包含的两个谷胱甘肽基之一稳定地结合到纳米颗粒表面。这通过用二硫苏糖醇还原其二硫键从结合的 GSSG 中释放 GSH 从实验上得到证实。我们的数据表明，GSSG 的两个谷胱甘肽基之一的羧酸盐基团通过静电相互作用主要负责 GSSG 与氧化铝表面的结合。这里呈现的结果和结论可以为进一步的实验和建模研究生物分子与陶瓷材料的相互作用提供基础。
