【作者】 徐学涛；

【导师】 张焜； 杜志云；

【作者基本信息】 广东工业大学 ， 应用化学， 2011， 博士

【摘要】 荧光探针具有高灵敏性、高选择性、非破坏性、特异性和时间可控性等优点,被广泛应用于分析化学、生物化学、细胞生物化学、医学等领域,特别是在生命科学领域。由于荧光探针技术在诸多领域中的重要应用,尤其在蛋白质基因工程中的应用,使得其成为目前国内外研究的热点。在本文中,以无毒、药效广泛的可食用性色素姜黄素为母体化合物,设计合成了一系列共七十个化合物。这类化合物结构中存在着二苯烯酮结构,可作为荧光探针的“荧光团”,而且烯酮结构中存在酮式与烯醇式之间的转换亦可为化合物提供特殊的光学性能。由此,本文用荧光法研究了二苯烯酮类化合物与pH值、酪氨酸酶、BSA之间的荧光响应。主要研究工作和结果如下：1二苯烯酮类化合物的合成本文选用常见的取代苯甲醛与酮为原料,在碱性条件下,以醛酮缩合机理,合成了七十个化合物。并用核磁共振、质谱等对其结构进行了表征。2二苯烯酮类化合物对pH值的响应研究了合成的化合物的紫外吸收光谱与荧光光谱对溶液pH值间的关系。结果显示,化合物的紫外吸收光谱与荧光光谱对pH值有强烈的依赖性。紫外吸收光谱在溶液酸碱性发生变化时,最大吸收峰发生红移,使得溶液颜色产生明显变化。同时,荧光光谱强度随着pH值的增加发生显著性增大。上述特性表明二苯烯酮类化合物可作为可视化pH荧光探针使用。其中3’-OCH3-4’-OH结构的类似物(A4、B4、C4、D4和E4)具有良好荧光性能。构效关系研究表明：4’-OH是化合物荧光性能的主要基团。在酚羟基邻位引入甲氧基能提高化合物的荧光性能,而引入溴则降低其荧光性能。此外,环戊酮类化合物相对于丙酮、环己酮、噻喃酮和吡喃酮类化合物具有较高的荧光性能。3二苯烯酮类化合物对酪氨酸酶的响应研究了酪氨酸酶对化合物荧光的猝灭。同时,发现化合物对酪氨酸酶有抑制作用。结果表明,酪氨酸酶对化合物的荧光具有猝灭功能。随着酪氨酸酶浓度的增加,化合物的荧光强度逐渐被猝灭,其中以含有邻二酚羟基结构的类似物猝灭性能最好。另一方面研究显示,化合物特别是带有酚羟基的二苯烯酮类似物对酪氨酸酶有显著的抑制作用。随着化合物浓度的增加,酪氨酸酶的活性逐渐降低,以含有邻二酚羟基结构的类似物(A6、B6、C6、D6和E6)抑制效果明显。最终分析表明酶动力学法和荧光光谱法所得结果可以相互验证。4二苯烯酮类化合物对BSA荧光的响应研究了合成化合物对BSA荧光的猝灭作用。结果显示,化合物对BSA荧光的有猝灭效果。其中,含有邻二酚羟基结构的类似物(A6、B6、C6、D6和E6)对BSA的猝灭常数和结合常数最大。构效关系研究表明,以芳香环上对位羟基为基准,在邻位引入羟基或者溴时,猝灭常数和结合常数变大；而引入甲氧基时猝灭常数和结合常数则变小。另外环戊酮类化合物相对于其他酮类化合物具有较高的猝灭常数和结合常数。更多还原

【Abstract】 It is well-known that fluorescent probes owning preferential properties such as high sensitivity, non-destructivity, specificity and timecontrollability had been widely used in analytical chemistry, bioanalytical chemistry, medicine and cellular biology, especially in the life sciences. Fluorescent probe technology was widely used in many fields, especially in Protein-Gene engineering, which made fluorescent probe techniques to be the hot research topics.In this study, seventy compounds were designed and synthesized based on curcumin, which was an eatable pigment with low toxicity and wildely medical and pharmacal activity. The distyryl ketone structure contained in those compounds was ordered as a "fluorophore". Further more, the conversion between keto form and enli form in ketene structure colud provide special optical properties. Since those compounds were derived from nature product curcumin, they also had the low toxicity.The studies of fluorescence properties of compounds mainly included the fluorescence response of compounds to pH values, tyrosinase and BSA. The main research works and results were sumerized as follows:1) Synthesis of compounds containing diphenyl ketene structureIn this paper, seventy compounds were synthesized with substituted benzaldehyde and ketone by aldol condensation under alkaline conditions. The structure was characterized by’H-NMR and MS.2) Fluorescent response of diphenyl ketene analogues to pH valueThe UV-absorption spectra and fluorescence spectra of compounds were investigated in different pH values. The results indicated that UV-absorption spectra and fluorescence spectra were strongly dependent on pH values. The maximum absorption peaks of absorption spectra of compounds were red shifted, while the environment changed from acidity to alkalinity, which made the solution of compounds undergo a distinct color change. Fourther more, the intensity of fluorescence spectra was enhanced significantly with the increase of pH values in alkaline conditions. Those features made compounds to be used as visable pH fluorescent probes. Compounds containing the 3’-OCH3-4’-OH on benzene ring (A4, B4, C4, D4, and E4) had favorable fluorescence property.Analyzing the relationship of stucture,4’-OH on benzene ring was found to be the key group for fluorescence, and fluorescence properties improved when a methoxy was introducted at the position of ortho-phenolic hydroxyl, while bromine made the contrary. In addition, fluorescence properties of compounds with cyclopentanone searies were better than compounds with acetone, cyclohexanone, thiapyrones and pyrones searies.3) Fluorescent response of diphenyl ketene analogues to tyrosinaseThe fluorescence quenching of tyrosinase on diphenyl ketene analogs and the inhibition of diphenyl ketene analogs on tyrosinase were studied. The tyrosinase showed the function to quenching the fluorescence of compounds. Fluorescence of compounds was gradually quenchinged by tyrosinase. Amongst, compounds containing ortho dihydroxyl groups did the best. At the same time, we found compounds had the inhibility on tyrosinase. Activity of tyrosinase was gradually reduced with increasing concentrations of compounds. Compounds containing ortho dihydroxyl groups showed remarkably potent inhibitory effects on tyrosinase. The results of enzyme kinetics and Fluorescent Spectrometry could check each other.4) Fluorescent response between diphenyl ketene analogues to BSAThe fluorescence quenching of diphenyl ketene analogues on BSA were investigated. The results indicated that compounds could quench the fluorescence of BSA. The quenching constant and binding constant of compounds containing ortho dihydroxyl groups were the largest.Analyzing the relationship of stucture,4’-OH on benzene ring was found to be the major groups, the quenching constants became larger when introducting the phenolichydroxyl or bromine at the ortho-position of 4’-OH, however the methoxy could make the quenching constants smaller. The quenching constants of cyclopentanone searies were better than other searies.更多还原