离子强度对大豆11S球蛋白表面疏水性及结构的影响

Effect of Ionic Strength on Surface Hydrophobicity and Structure of 11S Glycinin

对不同离子强度条件下大豆11S球蛋白溶解性、表面疏水性(H_0)、Zeta电位、粒径以及分子结构进行测定,探讨离子强度对大豆11S球蛋白H_0及结构的影响。离子强度由0增加到0.9,大豆11S球蛋白的溶解性降低,H_0增加,Zeta电位绝对值降低,平均粒径增加。此外,随着离子强度的增加,α-螺旋含量降低,β-折叠含量增加,蛋白质的酪氨酸和色氨酸残基由"包埋"态转变为"暴露"态,这种结构的变化可能导致H_0的增加。不同离子强度条件下大豆11S球蛋白的二硫键构型发生了改变,这可能会影响蛋白质的H_0。

Solubility,surface hydrophobicity(H0),Zeta potential,particle size and molecular structure of 11S glycinin at different ionic strengths were determined.The effect of ionic strength on H0 and structure of 11S glycinin was explored.Results showed that the solubility and absolute value of Zeta potential were decreased whereas H0 and average particle size were increased with increasing ionic strength from 0 to 0.9.Moreover,the content ofα-helix structure was decreased and the content ofβ-sheet structure was increased.The tyrosine and tryptophan residues of the protein was transformed from“embedding”to“exposure”state as the ionic strength was increased,leading to an increase of H0.The disulfide bond configuration of 11S glycinin at different ionic strengths was changed,possibly affecting its H0.