DSC studies on bovine serum albumin denaturation - Effects of ionic strength and SDS concentration
DSC studies on bovine serum albumin denaturation - Effects of ionic strength and SDS concentration
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DOI：
10.1016/s0141-8130(97)01159-8
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发表时间：
1997-06-01
影响因子：
8.2
通讯作者：
Barone, G
中科院分区：
文献类型：
--
作者：
Giancola, C;DeSena, C;Barone, G
本文分析了脱脂牛血清白蛋白（BSA）的热变性过程。通过改变pH、离子强度和十二烷基硫酸钠（SDS）浓度进行DSC测定。这些数据已与我们和其他作者先前获得的数据进行了比较。这些测量的目的是研究牛血清白蛋白天然蛋白结构的三维组织与其热力学稳定性之间的关系，并阐明球状蛋白与两亲分子之间的非共价相互作用。这些测量表明，无论pH、离子强度和SDS浓度如何，热变性总是不可逆的。讨论了叠加在蛋白质展开上的不可逆过程的性质。在0 ~ 1.0 m范围内，NaCl对BSA原生结构有较强的稳定作用。值得注意的是，在pH范围内的量热曲线不能用两态转换模型来表示；它们被反卷积为两个独立的两态转换的和。这些转变与BSA结构有关。十二烷基硫酸钠的净稳定作用可达10:1（配体与蛋白质）的摩尔比。在这个浓度范围内，SDS的存在导致了过剩热容量的双相分布。我们建立了一个简单的热力学模型，试图重现实验DSC分布，并收集有关SDS结合平衡的信息。(C) 1997爱思唯尔科学有限公司
This work analyzed the thermal denaturation process of defatted bovine serum albumin (BSA). DSC measurements were performed on changing the pH, the ionic strength and the sodium dodecyl sulfate (SDS) concentration. These data have been compared with those previously obtained by us and other authors. The purpose of these measurements was to study the correlation between the three-dimensional organization of BSA native protein structure and its thermodynamic stability and to clarify the non-covalent interactions between the globular proteins and amphipathic molecules. These measurements have shown that the thermal denaturation is always irreversible regardless of pH, ionic strength and SDS concentration. The nature of the irreversible process superimposed on the protein unfolding is discussed. The strong stabilizing effect of NaCl on the BSA native structure has been found for the range 0-1.0 M. It is worth noting that the calorimetric curves, confined to the pH region studied, could not be represented by a two-state transition model; they were deconvoluted as the sum of two independent two-state transitions. These transitions were correlated to the domain structure of BSA. Sodium dodecyl sulfate has a net stabilizing effect up to a molar ratio of 10:1 (ligand to protein). In this range of concentrations the presence of SDS causes a biphasic profile of excess heat capacity, A simple thermodynamic model was developed in attempt to reproduce the experimental DSC profiles and collect information regarding the binding equilibrium of SDS. (C) 1997 Elsevier Science B.V.