摘要
糖基化是生物体内广泛存在的翻译后修饰,对蛋白质的结构和功能有重要影响,研究了O-糖链对猕猴桃蛋白性质的影响。采用乙醇浸提法提取猕猴桃糖蛋白CGp,通过β-消除反应去除猕猴桃糖蛋白CGp上的O-糖链,得到产物CGpp。CGp和CGpp经Sepharose CL-6b凝胶色谱柱分离纯化后分别得到Gp1、Gp2和Gp1p、Gp2p。之后测定了4种蛋白的OH自由基、DPPH自由基、ABTS自由基清除能力。使用傅里叶红外变换光谱法测定了O-糖链释放前后猕猴桃糖蛋白的二级结构,通过Peakfit拟合指认二级结构吸收峰,得到不同二级结构所占比例。结果表明:4种蛋白质均具有一定的清除OH自由基、DPPH自由基和ABTS自由基的能力,且随着浓度增大而增大,具有明显的量效关系;O-糖链释放后猕猴桃糖蛋白的ABTS自由基清除能力显著增强;β-折叠结构含量与OH自由基、DPPH自由基的清除能力呈正相关。
China has an abundant resource of kiwi fruit,which has rich nutrition and strong antioxidant ability.Glycosylation widely exists in organisms as a kind of post translation modification,which significantly affects the structure and functions of proteins. The present study was to investigate the effects of O-glycan on the antioxidant activity and secondary structure of glycoprotein extracted from kiwi fruit. The glycoprotein was extracted from kiwi fruit by ethanol,which was named as CGp. O-glycan linked with CGp was released by β-elimination reaction and CGpp was afforded. Gp1,Gp2 and Gp1 p,Gp2p were afforded by the separation and purification of CGp and CGpp respectively with a Sepharose CL-6b gel column. The antioxidant abilities of Gp1,Gp2,Gp1 p,Gp2p were evaluated by the OH·,DPPH· and ABTS· radical scavenging experiments. The percentages of the secondary structures of four protein were determined by Fourier Transform Infrared spectrum and peak fitting method. The results showed that the four proteins all had the scavenging ability of OH·,DPPH· and ABTS·,and the ability had a dose-response relationship with the proteins concentration. Gp1 and Gp2 showed more effective ability of elimination ABTS· radicals after releasing of O-glycan. There existed a positive correlation between the percentage of β-sheet and scavenging ability of ·OH and DPPH·radicals.
出处
《河南工业大学学报（自然科学版）》
CAS
北大核心
2016年第2期79-85,共7页
Journal of Henan University of Technology：Natural Science Edition
基金
国家自然科学基金项目(31201294)
粮食公益性行业科研专项(201313011)
河南工业大学省属高校基本科研业务费专项(2014YWJC05)
关键词
猕猴桃
糖蛋白
O-糖链
抗氧化
二级结构
kiwi fruit
glycoprotein
O-glycan
antioxidant
secondary structure
