Effect of pH on the conformation of gellan chains in aqueous systems.
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.
Horinaka
Jun-ichi
J
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, A3-111, Takigawa laboratory Kyotodaigak, Nishikyo, Kyoto 615-8510, Japan. horinaka@rheogate.polym.kyoto-u.ac.jp
Kani
Kohei
K
Hori
Yuko
Y
Maeda
Shiro
S
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014867:Water
D011135:Polysaccharides, Bacterial; D012996:Solutions; D014867:Water; C048288:gellan gum