马铃薯丝氨酸蛋白酶抑制剂的分离纯化、结构特征及构象稳定性研究

项目名称： 马铃薯丝氨酸蛋白酶抑制剂的分离纯化、结构特征及构象稳定性研究

项目编号： No.31301532

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 农业科学

项目作者： 曾凡逵

作者单位： 中国科学院兰州化学物理研究所

项目金额： 23万元

中文摘要： 马铃薯块茎约含1.5%蛋白，其中约一半为蛋白酶抑制剂。过去长期把蛋白酶抑制剂当抗营养因子研究，近年来发现其具有抗癌和调节饮食的作用，在食品和制药工业中具有广阔的应用前景。马铃薯蛋白酶抑制剂重新成为马铃薯加工研究的热点。传统酸热絮凝法已导致马铃薯蛋白发生不可逆变性，回收的蛋白只能用作饲料。课题组的前期研究表明，扩张床吸附可用于从马铃薯淀粉加工分离汁水选择性回收具有天然活性的蛋白酶抑制剂，回收的蛋白含有多个蛋白酶抑制剂组分，且以丝氨酸蛋白酶抑制剂为主。本研究拟采用凝胶过滤、离子交换和疏水作用对马铃薯丝氨酸蛋白酶抑制剂进行分离纯化，筛选出相对含量和活力高的亚型，分别采用圆二色光谱、荧光光谱、FTIR和DSC对其结构和构象稳定性进行研究，明确pH和温度对蛋白α-螺旋、β-折叠、β-转角和无规则卷曲变化规律的影响，阐明马铃薯浓缩蛋白发生不可逆变性的机理，为食品级（药品级）马铃薯蛋白开发提供科学依据。

中文关键词： 马铃薯；丝氨酸蛋白酶抑制剂；分离纯化；结构特征；构象稳定性

英文摘要： Potato tubers contain approximately 1.5% protein on a fresh weight basis, of which, protease inhibitors represent up to 50%. Although protease inhibitors have been long considered only as antinutritional factors, potato protease inhibitors have regained interest in recent years because of their possible anticarcinogenic and positive dietary effects with broad prospects for application in the food and pharmaceutical industries. Conventional protein recovery in the milling industry includes deleterious steps like steam pressure coagulation and acid precipitation. This results in irreversible denatured proteins of only animal feed grade.Our previous study has shown that expanded bed adsorption can be used for recovery native protein from potato fruit water, the recovered protein contained a group of proteas inhibitors, with potato serine protease inhibitor as the main fraction. Therefore, the aim of the present study is to isolate potato serine protease inhibitor from potato fruit water by gel filtration, ion exchange and hydrophobic interaction chromatography, to screen out the most abundant isoform of potato serine protease inhibitor, to study the structure of potato sereine protease inhibitor and the effect of pH and temperature on the content of α-helix,β-strand, β-turn and random coil, to understand the mechai

英文关键词： potato；serine protease inhibitor；purification；structural properties；conformational stability