pH诱导的结构变化在牛血清白蛋白泡沫分离中蛋白质聚集中的作用

Li Rui, Wu Zhaoliang, Wangb Yanji, Ding Linlin, Wang Yanyan

School of Chemical Engineering and Technology, Hebei University of Technology, No.8 Guangrong Road, Dingzi Gu, Hongqiao District, Tianjin, 300130, China.

Key Laboratory of Green Chemical Technology & High Efficient Energy Saving, Hebei University of Technology, No. 8 Guangrong Road, Dingzi Gu, Hongqiao District, Tianjin, 300130, China.

Biotechnol Rep (Amst). 2016 Jan 22;9:46-52. doi: 10.1016/j.btre.2016.01.002. eCollection 2016 Mar.

For reducing protein aggregation in foam fractionation, the role of pH-induced structural change in the interface-induced protein aggregation was analyzed using bovine serum albumin (BSA) as a model protein. The results show that the decrease in pH from 7.0 to 3.0 gradually unfolded the BSA structure to increase the molecular size and the relative content of β-sheet and thus reduced the stability of BSA in the aqueous solution. At the isoelectric point (pH 4.7), BSA suffered the lowest level in protein aggregation induced by the gas-liquid interface. In the pH range from 7.0 to 4.7, most BSA aggregates were formed in the defoaming process while in the pH range from 4.7 to 3.0, the BSA aggregates were formed at the gas-liquid interface due to the unfolded BSA structure and they further aggregated to form insoluble ones in the desorption process.

为了减少泡沫分离中的蛋白质聚集，以牛血清白蛋白（BSA）作为模型蛋白，分析了pH诱导的结构变化在界面诱导蛋白质聚集中的作用。结果表明，pH从7.0降至3.0会使BSA结构逐渐展开，分子尺寸增大，β-折叠的相对含量增加，从而降低了BSA在水溶液中的稳定性。在等电点（pH 4.7）时，BSA在气液界面诱导的蛋白质聚集中处于最低水平。在pH值为7.0至4.7的范围内，大多数BSA聚集体在消泡过程中形成，而在pH值为4.7至3.0的范围内，由于BSA结构展开，BSA聚集体在气液界面形成，并在解吸过程中进一步聚集形成不溶性聚集体。