【作者】 周立斌；

【导师】 马建标；

【作者基本信息】 天津工业大学 ， 材料学， 2004， 硕士

【摘要】 环糊精及其衍生物具有疏水性空腔和亲水性外壁，作为主体分子可包络识别各种有机、无机和生物分子而形成主—客体超分子包合物，故作为优良的酶模型和分子受体在科学和技术等诸多领域有着极为广泛的应用。氨基酸是构成蛋白质的基本单元，通过对环糊精与氨基酸以及多肽之间包络识别行为的研究，对于认识生命现象的本质、理解超分子中的自组装、分子识别等概念具有十分重要的意义，并为进一步研究和认识环糊精高聚物与蛋白质之间的包络行为奠定基础。 本文研究了β—环糊精与芳香族氨基酸L—苯丙氨酸、L—酪氨酸和L—色氨酸之间的包合作用，考察了β—环糊精用量、温度、时间和pH值等因素对包合作用的影响。由于β—环糊精对芳香族氨基酸的疏水性识别作用，β—环糊精与芳香族氨基酸形成了包合物。从紫外光谱和荧光光谱测试结果表明，β—环糊精用量的增加、温度的降低、时间的延长，有利于β—环糊精与这三种芳香族氨基酸形成较为稳定的包合物。随着β—环糊精用量的增加和作用时间的延长，β—坏糊精对芳香族氨基酸的包合作用增强，揭示了β—环糊精与芳香族氨基酸包合物在水溶液中的形成是一动态平衡过程。温度的降低有利于β—环糊精与这三种芳香族氨基酸包合物的稳定性，表明包合过程是一热力学放热过程，即包合识别过程的熵变和焓变为分子识别和包合物稳定存在的驱动力之一。由于受主客体之间的尺寸匹配性的影响，β—环糊精与这三种芳香族氨基酸形成了不同包合比的包合物，β—环糊精分别与L—苯丙氨酸和L—酪氨酸形成了1：1的包合物，而与L—色氨酸却形成了2：1的包合物，各包合物的稳定常数也有所不同。总之，β—环糊精与这三种芳香族氨基酸之间的包合是多种因素协同作用的综合效果。 此外，进一步研究了β—环糊精及其聚乳酸接枝共聚物与客体胰岛素之间的包合作用，同样考察了β—环糊精用量、温度、时间和pH值等因素对包合识别作用的影响，结果显示主体β—环糊精及其聚乳酸接枝共聚物对客体胰岛素之间的包合作用和识别机理与β—环糊精对芳香族氨基酸的识别作用和识别机理类似。另外，紫外光谱和荧光光谱测定结果表明，由于胰岛素复杂的三维立体结构特点以及其聚集体表面极性基团对β—环糊精的空间位阻和排斥作用，日一环糊精单体与胰岛素之间存在着较弱的包合识别作用;而对于p一环糊精接枝聚乳酸共聚物，由于环糊精高聚物存在的高分子效应，即各环糊精单体之间的协同识别和高分子链的骨架效应等，与小分子环糊精单体的包合作用有显著的差异，与胰岛素之间则存在着稳定的包合作用。因此，p一环糊精及其聚乳酸接枝共聚物有望用作肤类药物释放体系的载体，并可能达到较高的载药量。更多还原

【Abstract】 Cyclodextrin and their derivatives have the hydrophobic cavities and hydrophilic wall. As the molecular host they are well known to have the property of forming inclusion complexes with organic, inorganic and biological molecules which possess suitable polarity and dimension. As the excellent enzyme model and molecule receptor, cyclodextrins have been widely used in many fields in science and technology. And peptides and proteins are composed of amino acids. The study on the inclusion behaviors of cyclodextrins with amino acids, peptides and proteins would help us to recognize the essence of life, the conception of self-assembly, molecular recognition and so on in the supramolecular chemistry. In our laboratory, supramolecular inclusion behaviors of polylactide- grafted copolymer of 3 梒yclodextrin with peptides and proteins were investigated so as to evaluated the possibilities of polylactide grafted copolymer of 3 梒yclodextrin as a carrier of pept.ide drug delivery system.The inclusion behaviors of B -cyclodextrin with some aromatic amino acids such as L-phenylalanine, L-tyrosine and L-tryptophan were studied via ultraviolet and fluorescent spectrometry. The results indicated that inclusion complexes of β-cyclodextrin with aromatic amino acids could be formed and the inclusion behaviors were affected by the amount of β-cyclodextrin, temperature and pH value. With the increase of β-cyclodextrin concentration, the decrease of temperature and prolongation of time, the inclusion complexes of β-cyclodextrin with these aromatic ami no acids became more stable. These results showed that the inclusion was a reversible equilibrium process and the inclusion of β-cyclodextrin with these aromatic amino acids was exothermic. The 1:1 inclusion complexes of β-cyclodextrin with phenylalanine and tyrosine were formed; but 2:1 complex was afford from β-cyclodextrin with tryptophan owing to the various sites and chaps of different amino acids.The inclusion behaviors of β-cyclodextrin and its polylactide-garfted copolymer with insulin were also studied via ultraviolet and fluorescent spectrometry. It was observed that the inclusion complexes of 3 -cyclodextrin and its polylactide-garfted copolymer with insulin could be formed and the inclusion behaviors were affected by the amount of 3 -cyclodextrin, temperature as well as pH value. The formation mechanism of the supramolecular systems between 3 -cyclodextrin and insulin was the similar to that between 3 -cyclodextrin and the above-mentioned aromatic amino acids. Because of the three-dimensional structure of insulin and the exterior polar groups of its aggregates, the molecular recognition and inclusion of 3 -cyclodextrin with insulin were hindered. As a result, there was a weak interaction between 3 -cyclodextrin and insulin. However, the interaction of polylactide-garfted copolymer of 0 -cyclodextrin with insulin was much stronger owing to the polymer effects of cyclodextrin polymer. The polymeric effects of polylactide-garfted copolymer of β-cyclodextrin, including cooperation effect, neighboring effect and polymer chain effect were discussed. Such a result suggested that polylactide-garfted copolymer of β-cyclodextrin would be a carrier of drug delivery system for peptides and proteins with high loading capacity.更多还原