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摘要
Water-soluble polypeptides bearing various pyridinium groups (i.e., pyridinium, 2-methylpyridinium, 3-methylpyridinium, 4-methylpyridinium) and Cl- counter-anions have been prepared by nuleophilic substitutions between poly(gamma-3-chloropropyl-L-glutamate) (PCPLG) or poly(gamma-6-chlorohexyl-L-glutamate) (PCHLG) and pyridine or y-methyl pyridine (y = 2, 3, and 4). Polypeptides bearing pyridinium groups and BF4- counter-anions were prepared by ion-exchange reactions from the polypeptide-pyridinium conjugates with Cl- counter-anions. CD analysis revealed that water-soluble polypeptides adopted alpha-helical conformation in solutions with a fractional helicity in the range of 24.7-41.4%. Variable-temperature UV-vis spectroscopy revealed that polypeptides bearing 3-methylpyridinium and BF4- counter-anions (i.e., P11 and P15) showed upper critical solution temperature (UCST)-type transitions in aqueous solutions. The UCST-type phase transition temperatures increased as increasing the hydrophobicity of the spacer groups, the polymer concentrations, and the concentrations of NaBF4.
- 出版日期2015
- 单位湘潭大学
