Arakawa T, Timasheff S N
Biochemistry. 1982 Dec 7;21(25):6545-52. doi: 10.1021/bi00268a034.
The preferential interactions of proteins with solvent components were studied in concentrated salt by densimetric measurements. Proteins were found to be preferentially hydrated in NaCl, NaCH3COO, and Na2SO4. The resulting unfavorable free-energy change was related to the effects of these salts on solubility and stability of the proteins. This unfavorable free-energy change was correlated with the large, positive surface tension increment of these salts, i.e., their perturbation of surface free energy. On the other hand, KSCN, CaCl2, and MgCl2 showed considerable binding to bovine serum albumin, which could be related to their destabilizing and salting-in effects on macromolecules. Since the last two salts have high surface tension increments, it was concluded that this does not necessarily lead to protein preferential hydration and stabilization.
通过密度测量研究了蛋白质在浓盐溶液中与溶剂成分的优先相互作用。发现蛋白质在氯化钠、醋酸钠和硫酸钠中优先水合。由此产生的不利自由能变化与这些盐对蛋白质溶解度和稳定性的影响有关。这种不利的自由能变化与这些盐的大的正表面张力增量相关，即它们对表面自由能的扰动。另一方面，硫氰酸钾、氯化钙和氯化镁与牛血清白蛋白有相当程度的结合，这可能与它们对大分子的去稳定化和盐溶作用有关。由于后两种盐有高的表面张力增量，得出的结论是这不一定导致蛋白质优先水合和稳定。
