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作者	单位
杨雪，叶麟，高玮，申光辉，黎杉珊，张志清	（1.四川农业大学食品学院，四川雅安 625014； 2.攀枝花市食品药品监督管理局，四川攀枝花 617000）

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中文摘要:

为了能更好地将麦麸酯酶用于检测食品中的农药残留，采用硫酸铵分段沉淀、透析、SephadexG-200凝胶层析、超滤浓缩等方法对麦麸中提取的酯酶粗液进行了分离和纯化，并对其酶学性质进行了研究。结果表明，得到的麦麸酯酶比活力为289.14 U·mg^-1，回收率为47.7%，纯化倍数为16.17。麦麸酯酶的分子量约为26.0 kDa，最大紫外吸收峰为224 nm和280 nm，最适反应温度为30 ℃，稳定范围为25～40 ℃；最适pH为8.0，pH稳定范围为4.0～8.0。Cu²⁺、Mg²⁺、Ca²⁺、Al³⁺、柠檬酸钠、四硼酸钠均对麦麸酯酶有抑制作用，而Fe²⁺、Mn²⁺、柠檬酸、硫酸铝钾对该酶有促进作用；以α-乙酸萘酯为底物的动力学参数K_m和V_max值分别为0.85 mg·mL^-1和0.93 mg·mL^-1·min^-1。4 ℃时，麦麸酯酶半衰期为10.4 d，而25 ℃时，酯酶半衰期为8.6 d。本研究结果对麦麸酯酶的应用具有一定参考价值。

英文摘要:

Collecting plant esterase from the wheat bran and studying the enzymatic properties in the experiment can provide worthful theoretical data for the application of wheat bran esterase in detecting pesticides in food. The liquid of crude enzyme extraction solution was purified by fractional ammonium sulfate precipitation,dialysis,SephadexG-200 gell filtration chromatography and ultrafiltration. The results showed that the specific activity of the enzyme was 289.14 U·mg^-1,and recovery of activity was 47.7%,and the purification fold was 16.17. The molecular weight of wheat bran esterase was 26.0 kDa,and the maximum ultraviolet absorption was at 224 nm and 280 nm. The optimum temperature is 30 ℃,with temperature stability range from 25 to 40 ℃. The optimum pH is 8.0,with stable range from 4.0 to 8.0. Esterase activity was inhibitied by Cu²⁺,Mg²⁺,Ca²⁺,Al³⁺,citric acid sodium,and sodium tetraborate,while it was enhenced by Fe²⁺,Mn²⁺,citric acid,and potassium aluminum sulfate. The esterase kinetic parameters K_m and V_max values with α-naphthyl acetate as substrate are 0.85 mg·mL^-1 and 0.93 mg·mL^-1·min^-1,respectively. The half-life were 10.4 and 8.6 d when storing at 4 and 25 ℃,respectively. This study made fundamental knowledge for using wheat bran esterase.

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