【摘要】 以乙酸香叶酯为底物,对大肠杆菌乙酰酯酶（Acetyl esterase,AES）的酶学性质进行解析,实现将乙酸香叶酯生物转化为香叶醇.结果显示:大肠杆菌AES酶的最佳反应p H范围为6.0-7.5;最适反应温度为30℃;最佳催化时间为2 h;Mg²⁺、Mn²⁺、Co²⁺对酶活没有太大影响,而Cu²⁺、Zn²⁺明显抑制酶的活性.对AES的动力学研究可知,其米氏常数Km、最大反应常数Vm分别为2.88 mmol/L、1.87 mmol/L.该酶同样可水解乙酸松油酯、乙酸薄荷酯、乙酸香茅酯,分别产生松油醇、薄荷醇和香茅醇.本研究得出了大肠杆菌乙酰酯酶的最适反应条件,可为后期香叶醇的生物合成优化和产量提高以及其他萜醇类化合物的生物合成提供参考依据.更多还原

【Abstract】 The enzymatic properties of Escherichia coli acetyl esterase（AES） were analyzed using geranyl acetate as a substrate, and the biotransformation of geranyl acetate to geraniol was realized. The results show that the optimum reaction p H range of AES enzyme was 6.0-7.5, the optimal reaction temperature was 30 °C, and the optimal catalytic time was 2 h. Mg²⁺, Mn²⁺, and Co²⁺ had little impact on enzyme activity, whereas Cu²⁺ and Zn²⁺ noticeably inhibited enzyme activity. Kinetic studies demonstrated that the kinetic parameters Km and Vm of the enzyme were 2.88 mmol/L and 1.87 mmol/L respectively. The enzyme also hydrolyzed terpinyl acetate, mint acetate, and citronella acetate, and produced terpineol, menthol, and geraniol respectively. The study obtained optimal reaction conditions for the E. coli acetyl ester enzyme, which supports biosynthesis optimization and an increase in the output of geraniol, and provides theoretical guidance for the biosynthesis of other terpenoids.更多还原