沉淀pH值对烟草Rubisco结晶的影响

Effect of precipitation pH on tobacco Rubisco crystallization

烟草Ｒｕｂｉｓｃｏ可以通过控制离子强度与ｐＨ形成六角形、十二面体结晶。晶体的形成受Ｒｕｂｉｓｃｏ沉淀过程中的ｐＨ值的影响。对Ｒｕｂｉｓｃｏ等电点ｐＨ的研究发现，ｐＨ５．０、ｐＨ５．１、ｐＨ５．２、ｐＨ５．３、ｐＨ５．４对Ｒｕｂｉｓｃｏ结晶的影响有明显的规律性；ｐＨ低，Ｒｕｂｉｓｃｏ沉淀速率与沉淀率高，沉淀物不规则，沉淀物复溶率低，结晶速率与结晶率低，对结晶时ｐＨ与离子强度选择范围窄，不利于晶体制备；ｐＨ高，Ｒｕｂｉｓｃｏ缓慢沉淀并形成晶体，沉淀速率与沉淀率虽低，但沉淀物复溶率高，结晶速率与结晶率高，对结晶时ｐＨ与离子强度的选择范围宽，有利于晶体制备。沉淀过程中，ｐＨ５．

Tobacco Rubisco could be crystallized under certain ion strength and pH.Crystallization of Rubisco was affected by Rubisco precipitation pH.Five pH values(5 0,5 1,5 2,5 3,5 4)were chosen in the process of Rubisco precipitation to investigate Rubisco precipitation,redissolution and crystallization.While pH was low,the precipitation speed and precipitation ratio were high,the precipitate was in an abnormal form,the redissolution ratio of Rubisco was low,the crystallization speed and crystallization ratio were low.In the process of crystallization,it was difficult to choose the crystallization ion strength and crystallization pH.While pH was high,the precipitation speed and precipitation ratio of Rubisco were low,the precipitate was in normal form,the redissolution ratio of Rubisco was high,and both the crystallization speed and crystallization ratio of Rubisco were high.In the process of crystallization,it was easy to choose the crystallization ion strength and crystallization pH.Precipitation pH 5 4 was the best pH for Rubisco crystallization.