紫色红曲霉FBKL3.0018产酯化酶的酶学性质研究

以从紫色红曲霉FBKL3.0018中固态发酵得到的粗酶制剂为研究对象，对该菌株的酯化酶酶学性质进行了较系统的研究。通过单因素实验确定该酶最适温度为40 ℃，在30 ℃条件下稳定性较好，最适pH值为6.5，在pH5.5～7.5条件下稳定性好。Fe2+、Na+、Mn2+、Mg2+、Li+、Zn2+对酯化酶酶活力有抑制作用，Ca2+在低浓度时有促进作用，高浓度时有抑制作用。K+对酯化酶酶活力有促进作用，并且随着K+浓度的升高，促进作用逐渐增强。吐温-80、十二烷基硫酸钠（SDS）、聚乙二醇6000、阿拉伯胶4种表面活性剂对酯化酶酶活力都有抑制作用。另外，甲醇和乙醇对该酯化酶酶活力有抑制作用，甲酸、乙酸、乳酸对酯化酶酶活力有促进作用。乙酸乙酯在低浓度时对酯化酶酶活力有抑制作用，含量为30%时反而有促进酶活力的作用。酯化酶最大反应速度Vmax为0.016 mol/（L·min），米氏常数Km为0.015 4 mol/L。

Enzymatic properties of esterifying enzyme from Monascus purpureus FBKL3.0018

Using the crude enzyme obtained from Monascus purpureus FBKL3.0018 by solid-state fermentation as research object, the enzymatic properties of the strain was studied systematically. By single factor experiments, the optimum temperature and pH of the enzyme was 40 ℃ and 6.5, respectively. The enzyme was stable at 30 ℃ and pH 5.5-7.5. Fe2+, Na+, Mn2+, Mg2+, Li+, and Zn2+ had inhibition effect on enzyme activity; Ca2+ showed promotion effect at low concentration, however, it showed inhibition effect at high concentration. K+ showed promotion effect on enzyme activity, and with the increase of K+ concentration, the promotion effect gradually enhanced. Tween-80, sodium dodecyl sulfate (SDS), polyethylene glycol-6000 and Arabic gum had inhibitory effect on enzyme activity. In addition, methanol and ethanol had inhibition effect on enzyme activity, formic acid, acetic acid and lactic acid had promotion function to enzyme activity. Ethyl acetate showed inhibition effect on esterifying enzyme activity at low concentration, but when the concentration was 30%, it showed promotion effect. The maximum reaction velocity (Vmax) of the esterifying enzyme was 0.016 mol/(L·min), Michaelis constant (Km) was 0.015 4 mol/L.