酰化对大豆蛋白分子结构影响的研究

Effect of succinic anhydride and acetic anhydride on the structure of soybean protein

目的:研究化学改性对大豆分离蛋白(SPI)分子结构的影响;方法:采用SDS-PAGE电泳、DSC热分析手段探讨酰化对蛋白分子结构特征的影响;结果:DSC图谱显示,SPI经过琥珀酰化处理后热稳定性得到显著改善,乙酰化处理对大豆蛋白的热稳定性影响不大。SDS-PAGE电泳结果显示,改性后蛋白的11S酸性亚基和7S含量大大减少,说明SPI经酰化处理后亚基发生了降解。随着酸酐添加量的增大,11S球蛋白分子逐步分解为亚基。琥珀酰化的电泳图谱预示着可能存在一个琥珀酰化的临界点,在这一点上,解离的蛋白亚基突然展开。结论:实验结果有助于阐明SPI酰化后功能性质发生变化的内在结构因素。

Objective： The effect of chemical modification on the structure of soybean protein isolate （SPI） was studied.Methods：SDS-PAGE and DSC were used to observe the dissociation of subunit proteins and the heat stability of acylated SPI respectively.Results：DSC profile showed that succinylation significantly improved the heat stability of SPI, while the acetylation had no significant change.SDS-PAGE profile showed that 7S globulin and most of the acid subunits of 1 ! S globulin disappeared due to acylation.lt was also indicated a cooperative process leading to a sudden unfolding of the dissociated subunits at a certain critical level of succinylation.Conclusion.The experiment results showing the changes in the structure properties of acylated SPI could help to elucidate the changes in its functional properties due to acylation.