【摘要】 本实验对Aspergillus ficuum产菊粉酶体系中的外切菊粉酶和内切菊粉酶的酶学性质进行了研究,研究表明二者酶学性质非常相似:两种酶的最适反应温度均在45℃左右;外切菊粉酶的最适反应pH为4.5,内切菊粉酶为pH5.0;Ag~+完全抑制两种酶的活性,Fe~2+和Al~3+对两种酶有较强的抑制作用,尤其是外切菊粉酶,Mg~2+对两种酶有激活作用;实验还对两种酶的动力学常数进行了测定和比较。更多还原

【Abstract】 Characteristics of two types of inulin-degrading enzymes from Aspergillus ficuum were studied. The optimum reaction temperature of endo- and exo-inulinase were around 45 ℃. The optimum reaction pH of endo-inulinase was 5.0, and that of exo-inulinase was 4.5. Both of them were stable within the pH range 4.0～8.0 and below the temperature 50 ℃. The metal ions had the different level influences on the purified enzymes. Endo-and exo-inulinase activities were completely inhibited by Ag+, and obviously by Fe2+ and Al3+, while Mg2+ had an activating effect. In addition the kinetic constants of the two enzymes were also studied.更多还原