酶的硫酸铵沉淀浓度范围的确定

The Determination of Saturation Percentages of Ammonium

采用分步连续沉淀酶方法 ,确定硫酸铵沉淀饱和百分数范围。在一只离心管中完成整个实验 ,避免了溶液转移以及计算与实际操作不一致带来的误差 ,并以上清液取样代替直接测定沉淀中含量 ,消除了沉淀不能与溶液彻底分净引起的误差。实验中测定了生物合成对 -氨基苯甲酸的氨基脱氧分枝酸合成酶和氨基脱氧分枝酸裂解酶的硫酸铵沉淀的饱和百分数范围 ,分别为 2 0 %到 70 %和 2 5 %到 5 5 % ,而最佳的提纯百分浓度范围为 2 5 %到 5 0 %和 2 5 %到 45 %。

This paper presents a multiple step and continuous precipitation experiment method to determine the accurate saturation percentages of ammonium sulphate precipitating enzymes.The experiment was carried out in a single centrifugal tube all along,avoiding the errors made in the transference of solution and those casued by the difference between the calculating and weighing.To eliminate determination errors brought about by the incomplete separation of precipate from supernatant,sampling in supernatant is adopted instead of the direct determination of precipate.The aminodeoxychorismate synthase and aminodeoxychorimate lyase were determined and their range of saturationb percentages of ammonium sulphate were 20% to 70% and 25% to 55% respectively.But their optimum range should be 25% to 50% and 25% to 45% according to the electrophoresis gel.