基于碘化钾-淀粉显色光度法测定过氧化氢酶活性

Determination of catalase activity by potassium iodide-starch spectrophotometric method

探讨碘化钾-淀粉显色光度法测定过氧化氢酶(CAT)活性的新方法。在硫酸介质中,双氧水氧化碘化钾生成碘,碘与淀粉快速反应呈现蓝色,根据酶促反应前后吸光度变化值△A确定CAT活性。结果表明,在30分钟内,酶促反应符合一级反应的特征,CAT活性E(U/mL)在0.002~0.04U/mL范围内且与△A呈良好的线性关系:△A=0.06843+16.9866E(U/mL),r=0.9970,检测限为0.0018U/mL。该方法用于鱼肝中CAT活性分析,平均回收率为100.5%,RSD=1.7~2.6%。

A new spectrophotometric method for the determination of catalase(CAT)in disinfectant was developed based on potassium iodide(KI)oxidation and discoloration.In sulfuric acid medium,H2O2 oxidizes potassium iodide to form iodine,and iodine quickly reacts with starch to give a blue color.Catalase activity was determined by the absorbance changes before and after the enzyme reaction.Within 30 minutes,the enzymatic reaction was fit for first order reaction.A linear equation for catalase activity E was:△A=0.06843+16.9866 E(U/mL),r=0.9970 in the range of 0.002~0.04 U/mL,and the detection limit was 0.0018 U/mL.The average recoveries for catalase in fish liver were 100.5%with a relative standard deviation of 1.7%~2.6%.