【摘要】 目的 :研究野生型无花果曲霉植酸酶的动力学性质 .方法 :通过限制培养基中的无机磷 ,无花果曲霉发酵获得植酸酶 .纯化后 ,对酶的动力学性质进行了研究 .结果 :该酶作用底物植酸钠的Km 值为 64.7μmol/L .对于植酸钠 ,植酸酶的最适反应pH为 5 .5温度为 5 0℃ .结论 :无花果曲霉植酸酶在pH 3.5～ 8.0 4 0℃以下比较稳定 ;不同的金属离子螯合剂对酶活性影响不一样 ,Ca2 + 对酶活力有轻微的激活作用 ,Al3 + 几乎无影响 ,Mg2 + 、Fe2 + 、Cu2 + 对酶活力有抑制作用 ,Co2 + 、Hg2 + 、EDTA有较强的抑制作用 .更多还原

【Abstract】 Aim: To study the kinetic characterization of phytase from Aspergillus ficuum. Methods: Phytase was obtained by cell culture of Aspergillus ficuum. During culture, the amount of inorganic orthophosphate was limited. Kinetic parameters of enzyme were detected after the purification of phyase. Results: Kinetic parameters of purified Aspergillus ficuum phytase were detected. Km for phytate was 64.7 μmol/L. The pH optima and temperature optima of phytase were 5.5 and 50℃, respectively. Conclusion: The enzyme was stable under condition of pH 3.5～8.0 and low 40℃. Aspergillus ficuum phytas had varied sensitivity towards cations. While Al 3+ produced no effect on the catalytic rate of the enzyme, Mg 2+, Fe 2+, Cu 2+, Co 2+, Hg 2+, EDTA were found to be inhibitory. Ca 2+ was observed to enhance enzyme activity.更多还原