Horinaka Jun-ichi, Kani Kohei, Hori Yuko, Maeda Shiro
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, A3-111, Takigawa laboratory Kyotodaigak, Nishikyo, Kyoto 615-8510, Japan.
Biophys Chem. 2004 Nov 1;111(3):223-7. doi: 10.1016/j.bpc.2004.06.003.
The optical rotation and fluorescence anisotropy for gellan aqueous systems were measured at pH 4, 7, and 10 to elucidate the effect of pH on the conformation of gellan chains. The optical rotation study suggests that pH affects the conformation of helical gellan chains and their aggregation behavior but the coil-helix transition temperature. By comparing the chain mobility estimated from the fluorescence anisotropy between different pH conditions, it has been revealed that the degree of expansion of random-coiled gellan chains varies with pH. These results indicate that the effect of pH is explained by the change in the anionic nature of gellan chains rather than in the shielding effect of hydrogen ions surrounding gellan chains as a cation species.
在pH值为4、7和10的条件下测量了结冷胶水溶液体系的旋光性和荧光 anisotropy，以阐明pH值对结冷胶链构象的影响。旋光性研究表明，pH值会影响螺旋状结冷胶链的构象及其聚集行为，但不影响其卷曲-螺旋转变温度。通过比较不同pH条件下由荧光anisotropy估算出的链迁移率，发现无规卷曲的结冷胶链的伸展程度随pH值而变化。这些结果表明，pH值的影响是由结冷胶链阴离子性质的变化来解释的，而不是由作为阳离子物种围绕在结冷胶链周围的氢离子的屏蔽效应来解释的。
