龙眼（Dimocarpus longan Lour.）单宁分离鉴定与抗酪氨酸酶机理研究

项目名称： 龙眼（Dimocarpus longan Lour.）单宁分离鉴定与抗酪氨酸酶机理研究

项目编号： No.31501414

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 农业科学

项目作者： 柴纬明

作者单位： 江西师范大学

项目金额： 20万元

中文摘要： 酪氨酸酶是黑色素生成和果蔬褐变等诸多生理过程中的关键酶，因而安全高效的酪氨酸抑制剂能有效地防止色素沉着性疾病和果蔬褐变的发生。我们前期研究发现植物单宁能高效地抑制酪氨酸酶的活性，但其内在的分子机制尚不清楚。基于植物单宁是一类酚类物质，结合酶的结构特点，我们推测，作为酶的底物类似物，植物单宁通过与底物竞争酶的活性位点来影响酪氨酸酶的活性。为证实这个假说，本项目拟以龙眼单宁为对象，研究其对酪氨酸酶的抑制效果及动力学，并进一步探讨其对酶的作用位点及内在的分子机制。鉴于植物单宁的生物活性很大程度上依赖于其纯度与结构，因而本项目联合使用柱色谱、MALDI-TOF MS、LC-MS和NMR等方法对龙眼单宁进行分离纯化与结构鉴定。本项目的实施，将有助于阐明植物单宁在农业、食品及医疗化工领域的应用，其结果可能为解决皮肤色素沉着和果蔬褐变等问题提供新思路，具有较强的理论意义和实际应用价值。

中文关键词： 酪氨酸酶；植物单宁；结构与活性；小分子与蛋白相互作用

英文摘要： Abstract: Tyrosinase is a key enzyme that is responsible for melanin biosynthesis in organisms and browning in fruits and vegetables. Therefore, tyrosine inhibitors safe and efficient are useful for prevention of pigmentation diseases and browning of fruits and vegetables. In our previous study, the results suggested that vegetable tannins are efficient inhibitors on tyrosinase activity. However, intrinsic molecular mechanism of inhibition is still unclear. Based on the structural characteristics of vegetable tannin (it is a class of phenolic compounds) and the enzyme, we speculate that vegetable tannins inhibit the activity of tyrosinase by competing active site of the enzyme, because they are the analog of enzyme substrate. To confirm the hypothesis, longan tannins are used as object to investigate their inhibitory effect and dynamics on the tyrosinase, and also explore their binding site on the enzyme and internal molecular mechanism. The biological activity of vegetable tannins is generally recognized to be largely depending on their purity and structure, therefore theses compounds are purified, isolated and identified through column chromatography, MALDI-TOF MS, LC-MS and NMR in this study. It is helpful to elucidate applications of vegetable tannins on agriculture, food, medical, and chemical industry follow the implementation of this project. The results probably provide new idea for solving skin pigmentation and browning of fruits and vegetables, which is significant for theory and practical application.

英文关键词： Tyrosinase; Vegetable tannin;Structure and biological activity;Interaction of small molecule and protein