囊泡表面分子间通讯交流体系的构建: 利用受体的分子识别行为调控酶的活性

在人工双层膜囊泡表面, 构建了一个通过人工受体的分子识别行为控制酶反应活性的超分子体系. 体系以生物体细胞信号转导系统为模拟原型, 由作为受体的烷基胺、被受体识别的信号分子吡哆醛衍生物、乳酸脱氢酶、受体和酶之间的媒介物Cu^2＋以及作为体系载体的合成肽脂囊泡五个成分构成．通过UV-vis光谱法及动态光散射测定对体系进行了评价, 结果表明: 随着受体疏水参数增大, 其对信号分子的识别能力增强, 二者呈良好的线性关系; 通过信号分子与囊泡表面静电相互作用的研究表明信号分子具有选择性; 媒介物与信号分子–受体可形成化学计量比为1∶2的配合物, 其形成能力比媒介物与酶的结合能力更强．作为结论, 体系中烷基胺受体对磷酸吡哆醛信号分子的识别有效控制了处于囊泡表面的乳酸脱氢酶的活性．

Intermolecular Communication on Lipid Bilayer Membrane: Molecular Recognition Behavior in the Receptor Site to Control Enzymatic Activity

Functionalized lipid bilayer vesicles on which molecular recognition by an artificial receptor synchronized with catalytic reaction by an enzyme were prepared in aqueous media. The system was constructed with the following molecular components: an alkyl amine as a receptor, a pyridoxal derivative as a signal ligand to the receptor, lactate dehydrogenase as an enzyme, Cu^2＋ ions as a mediator between the receptor and the enzyme, and a synthetic peptide lipid as a membrane-forming amphiphile. The design of the present supramolecular assembly was inspired by biological signal transduction system on the cell membrane. Molecular recognition behavior of the signal ligand by the receptor was well correlated with the hydrophobic parameter of the receptor molecules. Marked signal specificity through electrostatic interactions between the signal and the membrane surface was also observed. Strong binding of the mediator species toward the signal-receptor complex in 1∶2 stoichiometry was clarified. As a result, the enzymatic activity on the membrane surface was effectively controlled through molecular recognition by a hydrophobic alkyl amine as the receptor toward pyridoxal 5'-phosphate as the signal ligand.