沉淀离子强度对烟草Rubisco结晶的影响

Effect of precipitation ion strength on tobacco Rubisco crystallization

稀释结晶法是Ｒｕｂｉｓｃｏ结晶的有效方法。稀释结晶与Ｒｕｂｉｓｃｏ的沉淀提取步骤中的离子强度关系密切。ｐＨ５．４沉淀Ｒｕｂｉｓｃｏ，提高沉淀过程中的离子强度，有利于提高Ｒｕｂｉｓｃｏ沉淀的复溶率与结晶率和提高Ｒｕｂｉｓｃｏ结晶时ｐＨ与离子强度选择范围，使Ｒｕｂｉｓｃｏ的稀释结晶提取方法更有效便捷。ｐＨ５．０下沉淀Ｒｕｂｉｓｃｏ，其复溶稀释结晶耗时长、收率低、方法不稳定。通过提高沉淀过程中的离子强度，其复溶液中Ｒｕｂｉｓｃｏ的复溶率与结晶率均较对照有显著提高。Ｒｕｂｉｓｃｏ沉淀过程中的离子强度直接影响到Ｒｕｂｉｓｃｏ沉淀物的规则性、沉淀的复溶率、复溶Ｒｕｂｉｓｃｏ的Ａ２８０／Ａ２６０值、ＯＤ３９０值，对结晶速率、结晶率以及结晶对ｐＨ与离子强度条件的选择范围均有重要影响。离子强度的选择控制在０．６ｍｏｌ·Ｌ－１－１．５ｍｏｌ·Ｌ－１ＮａＣｌ合适，过低与过高均不利于Ｒｕｂｉｓｃｏ的结晶。

Tobacco Rubisco could be crystallized by the method of dilution.Rubisco crystallization was affected by the ion strength in the process of Rubisco precipitation.As to pH 5 4 precipitation,the increment of ion strength increased the redissolution ratio,crystallization ratio of precipitated Rubisco and expanded the pH and ion strength scale for Rubisco crystallization.The combination of pH 5 4 and 1 0mol·L -1 NaCl made Rubisco crystallization easier under dilution condition.As to pH 5 0 precipitation,Rubisco crystallization had low recovery ratio with the process of time consuming.Increasing ion strength could improve the redissolving ratio and crystallization ratio in Rubisco precipitation.The ion strength choice directly affected the redissolution ratio and crystallization ratio of precipitable Rubisco and the choice between pH and ionstrength in the process of crystallization.The 0 6mol·L -1 1 5mol·L -1 NaCl was the best range of ion strength in comparing with lower or higher NaCl concentration.