醇变性大豆7S球蛋白结构特征研究

利用不同体积分数乙醇溶液对大豆7S球蛋白进行变性。分别对醇变性大豆7S球蛋白溶解度、表面疏水性、二级结构和聚集形态进行分析。大豆7S球蛋白经醇溶液变性后,溶解度在乙醇体积分数为55%~65%时基本达到最低值;表面疏水性在乙醇体积分数为25%和65%时分别达到最大值和最小值。傅立叶红外光谱表明,在乙醇体积分数较低时,β-折叠结构能稳定存在;在乙醇体积分数较高时,β-折叠和α-螺旋之间结构发生转变,呈现较高螺旋态。凝胶电泳表明,7S球蛋白亚基间以非共价相互作用力为主;经醇变性后,导致聚集体产生,且7S球蛋白分子间非共价相互作用随乙醇体积分数增大呈有逐渐增大趋势。

Study on structure characteristics of ethanol-denatured 7S globulin in soybean

In order to study on the structure characteristics of ethanol-denatured 7S globulin in soybean,solubility,surface hydrophobicity,secondary structure and aggregates of 7S globulin in soybean denatured by the different volume fraction of ethanol solution was investigated.The results showed that when the ethanol volume fraction is 55%,Solubility of 7S globulin in soybean via denaturation of ethanol solution reach to minimum.When the ethanol volume fraction is between 25% and 65%,surface hydrophobicity respectively reached to maximum and minimum.FTIR demonstrated that beta-sheet could stability at lower volume fraction of ethanol solution,and the transform between beta-sheet and alpha-helix would happen at higher volume fraction of ethanol solution.SDS-PAGE analysis showed that the intra-subunit interaction of 7S globulin mainly is non-covalent interaction,and increasing the volume fraction of ethanol led to increased inter-molecule non-covalent interaction of 7S globulin,and come into being protein aggregates.