Instituto de Física Aplicada INFAP-FQBF-UNSL-CONICET, Av. Ejército de los Andes 950, Bloque III, D5700HHW, San Luis, Argentina.
Instituto Multidisciplinario de Investigaciones Biológicas IMIBIO-FQBF-UNSL-CONICET, Ejército de los Andes 950, Bloque III, D5700HHW, San Luis, Argentina.
Carbohydr Polym. 2019 Feb 15;206:57-64. doi: 10.1016/j.carbpol.2018.10.102. Epub 2018 Nov 1.
Sorption of l- and d-Tyrosine (Tyr) from aqueous solutions on chiral membranes of chitosan (CH) was studied. A high adsorption in the membrane, with a marked enantioselectivity to l-Tyr, was found. Computational calculations carried out by docking and molecular dynamics (MD) showed a difference in the affinity of the enantiomers and two regions of adsorption in the polymer matrix. The interactions of the enantiomers with the polymer matrix were studied by using FTIR, DRx, DSC and TG measurements. These results indicate that adsorption of Tyr reduces the crystallinity of the membrane and generates a rearrangement of the chains, decreasing the intercatenary spacing. Also, it was observed that the hydrated polymorph to anhydrous polymorph ratio has changed during adsorption, that is, water bound to chitosan is also modified. The energy balance of the system hydrogen bonding, desolvation and the conformational changes resulted in a spontaneous and endothermic process.
从水溶液中对映体吸附 L-和 D-酪氨酸（Tyr）在壳聚糖（CH）手性膜上进行了研究。在膜中有很高的吸附性，对 L-Tyr 表现出明显的对映体选择性。通过对接和分子动力学（MD）计算表明，手性聚合物基质中对映体的亲和力和吸附区域存在差异。通过傅里叶变换红外光谱（FTIR）、DRx、差示扫描量热法（DSC）和热重分析（TG）测量研究了对映体与聚合物基质的相互作用。这些结果表明，Tyr 的吸附降低了膜的结晶度，并导致链的重排，减小了链间间距。此外，还观察到在吸附过程中，水合多晶型到无水多晶型的比例发生了变化，即与壳聚糖结合的水也发生了变化。氢键、去溶剂化和构象变化的能量平衡导致了一个自发的吸热过程。
