食品科学

• 基础研究 • 上一篇    下一篇

大米镉结合蛋白的分离及理化特性

刘珊珊1,陈季旺1,2,*,陈 露1,丁文平1,2,吴永宁1,3   

  1. 1.武汉轻工大学食品科学与工程学院,湖北 武汉 430023;2.农产品加工湖北省协同创新中心,湖北 武汉 430023;
    3.国家食品安全风险评估中心,北京 100021
  • 出版日期:2015-12-15 发布日期:2015-12-24

Separation and Physicochemical Characteristics of Cd-Binding Protein in Rice

LIU Shanshan1, CHEN Jiwang1,2,*, CHEN Lu1, DING Wenping1,2, WU Yongning1,3   

  1. 1. College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China;
    2. Hubei Collaborative Innovation Center for Processing of Agricultural Products, Wuhan 430023, China;
    3. China National Center for Food Safety Risk Assessment, Beijing 100021, China
  • Online:2015-12-15 Published:2015-12-24

摘要:

本实验选用一种镉含量较高的大米为原料,采用碱法提取大米蛋白(alkali-extractable protein,AP),依次用热变性和乙醇沉淀分离AP,制备大米镉结合蛋白(rice Cd-binding protein,RCBP),并分析了RCBP的紫外吸收特征、氨基酸组成、分子质量及二级结构。结果显示:AP、热变性蛋白(thermally denaturated protein,TP)和乙醇沉淀蛋白(ethanol-precipitated protein,EP)均在210 nm波长处有最大吸收峰,氨基酸组成类似;热变性去除了分子质量为94 kD的蛋白质,分子质量为5 094 kD的蛋白质含量减少,乙醇沉淀进一步减少了分子质量分别为50 kD和14 kD的蛋白质。AP的二级结构主要为α-螺旋和β-转角,有少量β-折叠;TP的二级结构只含有β-折叠和β-转角,且以β-折叠为主;EP的二级结构主要为β-折叠和β-转角,还含有少量α-螺旋和无规卷曲。表明热变性和乙醇沉淀使得AP中的镉结合蛋白得到分离,可以作为一种分离RCBP的方法。

关键词: 大米镉结合蛋白, 热变性, 乙醇沉淀, 理化性质

Abstract:

Rice Cd-binding protein (RCBP) was obtained from high-Cd rice using alkali extraction, thermal denaturation
and ethanol precipitation. Physicochemical characteristics including UV absorbance, amino acid composition, molecular
weight and secondary structures were investigated. The results showed that all the alkali-extractable protein (AP), thermally
denaturated protein (TP) and ethanol-precipitated protein (EP) had the maximum absorption peak at 210 nm and similar
amino acid composition. The 94-kD protein was completely removed and the 5 094-kD protein was decreased by the thermal
denaturation. Moreover, the ethanol precipitation resulted in a further reduction of the 50-kD and 14-kD proteins. The major
secondary structures of AP were α-helical and β-turn, while β-sheet and β-turn were found in TP. On the other hand, β-sheet
and β-turn were predominant in EP. These results indicated that thermal denaturation and ethanol precipitation could be used
to separate RCBP from AP.

Key words: rice Cd-binding protein, thermal denaturation, ethanol precipitation, physicochemical characteristic

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