纳豆激酶稳定性研究

Study on the Stability of Nattokinase

目的：研究温度、pH、金属离子对纳豆激酶稳定性的影响。方法：采用琼脂糖—纤维蛋白平板法测定活性。结果：纳豆激酶在低于40℃相对稳定,高于45℃时活性下降趋势明显,55℃活性完全丧失;纳豆激酶的最适pH为7.0,在6.0～9.0相对稳定;Mg^2＋、Ca^2＋、Na^＋对于NK有明显的激活作用,低浓度K＋没有明显的激活或抑制作用,高浓度的K＋对纳豆激酶的活性有抑制作用,Fe^2＋、Zn^2＋、Cu^2＋、Ba^2＋、Al^3＋、Mn^2＋对NK的活性有不同的抑制作用。结论：纳豆激酶的保存温度要低于40℃,pH值在6.0～9.0的环境下,也可适当加入Mg^2＋、Ca^2＋、Na^＋增加NK的稳定性。

Objective：To study the effect of temperature,pH and metal ions on the stability of nattokinase. Methods：The activity of nattokinase was determined by agarose-fibrin plate method. Results：Nattokinase is relatively stable below 40 ℃,decreased significantly at higher than 45 ℃,and activity is completely lost at 55 ℃. The optimum pH of nattokinase is 7.0,relatively stable at 6.0-9.0;the activity of NK is obviously enhanced by Mg^2＋,Ca^2＋ and Na＋;Low concentration of K^＋ has no obvious activation or inhibition,while high concentration of K^＋ has inhibitory effect;Fe^2＋,Zn^2＋,Cu^2＋,Ba^2＋,Al^3＋ and Mn^2＋ have different inhibitory effects on NK activity. Conclusion：The storage temperature of nattokinase should be lower than 40 ℃,and the pH value should be between 6.0-9.0. The stability of NK could be improved by adding Mg^2＋,Ca^2＋,Na^＋.