Romero Carmen M, Trujillo Ginna P, Verissimo Luis M P, Esteso Miguel A, Ramos M Luísa, Ribeiro Ana C F
Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia Sede Bogotá, Calle 44 No. 45-67 - Bloque B-09, Bogotá D.C., Colombia.
Centro de Química and Department of Chemistry, University of Coimbra, 3004-535, Coimbra, Portugal.
Eur Phys J E Soft Matter. 2019 Jul 23;42(7):94. doi: 10.1140/epje/i2019-11856-1.
Transport properties of model compounds in aqueous solutions such as amino acids can provide valuable information in order to understand the complex interactions in aqueous solutions as well as the protein stability in water and the relevant factors involved. Informations about the diffusion of amino acids in water and in aqueous solutions of sodium chloride are very scarce, especially for the 5-aminopentanoic acid and 6-aminohexanoic acid. In this study, limiting binary mutual diffusion coefficients at 298.15 K of 5-aminopentanoic and 6-aminohexanoic acids in aqueous solutions of NaCl 0.15 mol kg, using the Taylor dispersion technique, were determined and the results compared with the limiting binary mutual diffusion coefficients for 2-aminopentanoic acid, and 2-aminohexanoic acid, obtained in the same experimental conditions. The discussion of the properties of the selected amino acids is centered on the positions of the ionic groups in the hydrocarbon chain and, in addition, we have discussed the effects of NaCl on their structures and properties. The data on diffusion properties are supported by H, C and Na NMR experiments, which we have obtained for 5-aminopentanoic and 6-aminohexanoic acids, in aqueous solution, also in the presence of NaCl.
诸如氨基酸等模型化合物在水溶液中的传输性质，可为理解水溶液中的复杂相互作用以及蛋白质在水中的稳定性及相关影响因素提供有价值的信息。关于氨基酸在水和氯化钠水溶液中的扩散信息非常稀少，尤其是对于5 - 氨基戊酸和6 - 氨基己酸。在本研究中，使用泰勒分散技术测定了298.15 K时5 - 氨基戊酸和6 - 氨基己酸在0.15 mol kg氯化钠水溶液中的极限二元互扩散系数，并将结果与在相同实验条件下获得的2 - 氨基戊酸和2 - 氨基己酸的极限二元互扩散系数进行比较。对所选氨基酸性质的讨论集中在烃链中离子基团的位置上，此外，我们还讨论了氯化钠对其结构和性质的影响。扩散性质的数据得到了我们针对5 - 氨基戊酸和6 - 氨基己酸在水溶液中（同样存在氯化钠）所进行的氢、碳和钠核磁共振实验的支持。
