title: Effect of pH on the conformation of gellan chains in aqueous systems.
abstract: 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.
authors.affiliation: 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
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Horinaka
authors.forename: Kohei
authors.initials: K
authors.lastname: Kani
authors.forename: Yuko
authors.initials: Y
authors.lastname: Hori
authors.forename: Shiro
authors.initials: S
authors.lastname: Maeda
mesh_terms: 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
chemical_list: D011135:Polysaccharides, Bacterial; D012996:Solutions; D014867:Water; C048288:gellan gum