Physical and Inorganic Chemistry Division, Central Leather Research Institute, Council of Scientific and Industrial Research (CSIR), Adyar, Chennai, Tamil Nadu, India.
Colloids Surf B Biointerfaces. 2011 May 1;84(1):172-80. doi: 10.1016/j.colsurfb.2010.12.029. Epub 2011 Jan 7.
The aggregation properties of Tyr-Phe dipeptide and Val-Tyr-Val tripeptide were studied in aqueous solution and in the presence of SDS and SDS-polymer environments using UV-visible, surface tension, fluorescence and circular dichroism (CD) techniques. Both the peptides formed micelles. The cmc values obtained for dipeptide and tripeptide are 2×10(-5) and 4×10(-5) M, respectively in aqueous solution at 25°C. The presence of additives (SDS and polymer) hindered the micelle formation of peptides. The cmc values obtained by various methods are in good agreement with each other. Effect of peptides on the aggregation properties of SDS also was investigated. The cmc of SDS was decreased in presence of peptides and were reduced with increase in temperature. Using monophasic micellization concept, the association constant (K(A)) for the SDS-peptide mixed micellar systems was determined. Using biphasic model, the thermodynamic parameters viz; ΔG°(m), ΔH°(m) and ΔS°(m) for SDS-water and SDS-peptide-water mixed micellar systems, the standard free energy for transfer of SDS from aqueous to peptide additive environments were estimated at various temperatures. These results suggest that the SDS is more stable in micellized form in the SDS-water-peptide ternary systems compared to the situation in the corresponding SDS-water binary systems.
在水溶液中和 SDS 及 SDS-聚合物环境中，使用紫外-可见分光光度法、表面张力法、荧光法和圆二色性（CD）技术研究了 Tyr-Phe 二肽和 Val-Tyr-Val 三肽的聚集性质。两种肽都形成胶束。在 25°C 的水溶液中，二肽和三肽的 cmc 值分别为 2×10(-5) 和 4×10(-5) M。添加剂（SDS 和聚合物）的存在阻碍了肽的胶束形成。各种方法得到的 cmc 值彼此吻合良好。还研究了肽对 SDS 聚集性质的影响。在肽存在下，SDS 的 cmc 值降低，并且随着温度的升高而降低。使用单相胶束化概念，确定了 SDS-肽混合胶束体系的缔合常数（K(A)）。使用双相模型，估算了 SDS-水和 SDS-肽-水混合胶束体系的热力学参数即 ΔG°(m)、ΔH°(m)和 ΔS°(m)，以及 SDS 从水相转移到肽添加剂环境的标准自由能，在不同温度下进行了研究。这些结果表明，与相应的 SDS-水二元体系相比，SDS 在 SDS-水-肽三元体系中的胶束化形式更稳定。
