Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia - 80126 Napoli, Italy.
Phys Chem Chem Phys. 2018 Nov 28;20(46):29389-29398. doi: 10.1039/c8cp04421j.
DSC measurements on RNase A at neutral pH show that five stabilizing agents, namely trimethylamine N-oxide, glucose, sucrose, betaine and sodium sulfate, can counteract the destabilizing action of urea, sodium perchlorate, guanidinium chloride and guanidinium thiocyanate. This is an important finding inferring that counteraction has a common physical origin, regardless of the chemical differences among the stabilizing agents and among the destabilizing ones. A rationalization is provided grounded on the following line of reasoning: (a) the decrease in solvent-excluded volume effect is the main stabilizing contribution of the native state; (b) its magnitude increases on increasing the density of the aqueous solution; (c) the density increases significantly in the ternary solutions containing water, a stabilizing agent and a destabilizing one, as indicated by the present experimental data.
在中性 pH 下对 RNase A 进行的 DSC 测量表明，五种稳定剂，即三甲基氧化胺、葡萄糖、蔗糖、甜菜碱和硫酸钠，可以抵消脲、高氯酸钠、盐酸胍和硫氰酸胍的去稳定作用。这是一个重要的发现，表明拮抗作用具有共同的物理起源，而与稳定剂和去稳定剂之间的化学差异无关。根据以下推理提供了合理化解释：(a)溶剂排除体积效应的减小是天然状态的主要稳定贡献；(b)随着水溶液密度的增加，其幅度增加；(c)如本实验数据所示，在包含水、一种稳定剂和一种去稳定剂的三元溶液中，密度显著增加。
