Interplay of ion specificity, pH and buffers: insights from electrophoretic mobility and pH measurements of lysozyme solutions
Interplay of ion specificity, pH and buffers: insights from electrophoretic mobility and pH measurements of lysozyme solutions
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DOI：
10.1039/c3ra00063j
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发表时间：
2013-01-01
期刊：
影响因子：
3.9
通讯作者：
Salis, Andrea
中科院分区：
文献类型：
--
作者：
Cugia, Francesca;Monduzzi, Maura;Salis, Andrea
离子专一性是化学和生物学中一个长期未解决的难题。无数的实验强调了它的普遍性。我们已经研究了在相同的标称散装pH值的不同缓冲液的离子的具体影响。我们使用了电泳光散射和pH值测量来研究由溶解在不同的缓冲溶液（TrisHCl，碳酸盐，cacodylate，磷酸盐，柠檬酸盐）的溶菌酶组成的系统。每种缓冲液具有相同的初始标称pH值（7.15）。实验在三种钠盐（NaCl、NaNO3、NaSCN）存在下进行。结果是明确的。我们发现，缓冲液类型强烈影响电泳迁移率和pH值的盐溶菌酶解决方案。缓冲剂所起的作用与不同钠盐所起的作用一样重要。我们还研究了由于用钾取代钠而引起的显著的额外的共离子特异性效应。由于离子特异性、pH值和缓冲液类型之间的相互作用而观察到的效应具有先前未认识到的重大影响。
Ion specificity is a long standing unsolved puzzle of chemistry and biology. Myriad experiments underline its universality. We have studied ion specific effects on different buffers at the same nominal bulk pH. We used both electrophoretic light scattering and pH measurements to investigate a system constituted by lysozyme dissolved in different buffer solutions (TrisHCl, carbonate, cacodylate, phosphate, citrate). Each buffer had the same initial nominal pH (7.15). The experiments were done in the presence of three sodium salts (NaCl, NaNO3, NaSCN). The results are unequivocal. We found that buffer type strongly affects electrophoretic mobility and the pH of salt-lysozyme solutions. The role played by the buffer is as important as that played by the different sodium salts. We also investigated striking additional co-ion specific effects due to the substitution of sodium with potassium. The observed effects due to an interplay among ion specificity, pH and buffer type have major implications not previously recognised.