Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.
Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.
Int J Biol Macromol. 2018 Feb;107(Pt B):2598-2603. doi: 10.1016/j.ijbiomac.2017.10.141. Epub 2017 Oct 24.
Pullulan is soluble in both N,N-dimethylacetamide (DMAc) and LiCl/DMAc. Here, the solution-state structures of pullulan in these two solvents were studied by size-exclusion chromatography with multi-angle laser light scattering (SEC/MALLS) and nuclear magnetic resonance (NMR) analyses. SEC/MALLS and off-line refractive index analyses revealed that the hydroxy groups of pullulan interact with LiCl in DMAc, as observed previously for cellulose. The nine different COH protons of pullulan in DMAc and LiCl/DMAc appeared independently in NMR spectra and were successfully assigned. When LiCl was present, the degree of dissociation of all COH protons of pullulan was increased by Li and Cl ions, and the conformations of the COH groups became stable and restricted in DMAc. Based on the obtained results, the solution-state structures of cellulose in LiCl/DMAc are hypothesized to contain similar interactions between the cellulose hydroxy groups, and Li and Cl in LiCl/DMAc to those observed for pullulan.
普鲁兰多糖可溶于 N,N-二甲基乙酰胺 (DMAc) 和氯化锂/二甲基乙酰胺 (LiCl/DMAc)。在此，通过尺寸排阻色谱法与多角度激光光散射 (SEC/MALLS) 和核磁共振 (NMR) 分析研究了普鲁兰多糖在这两种溶剂中的溶液结构。SEC/MALLS 和离线折射率分析表明，普鲁兰多糖的羟基与 DMAc 中的 LiCl 相互作用，这与纤维素的先前观察结果一致。普鲁兰多糖在 DMAc 和 LiCl/DMAc 中的九个不同的 COH 质子在 NMR 光谱中独立出现，并成功进行了分配。当存在 LiCl 时，普鲁兰多糖所有 COH 质子的离解度都被 Li 和 Cl 离子增加，并且 COH 基团的构象在 DMAc 中变得稳定和受限。基于获得的结果，假设纤维素在 LiCl/DMAc 中的溶液结构包含纤维素羟基、Li 和 Cl 在 LiCl/DMAc 之间的类似相互作用，这些相互作用与观察到的普鲁兰多糖相似。
