Chemistry Department, Faculty of Science, Muğla Sıtkı Koçman University, Muğla, Turkey.
Prep Biochem Biotechnol. 2013;43(8):750-65. doi: 10.1080/10826068.2013.773340.
The scope of this study is to achieve carrier-bound immobilization of catalase onto magnetic particles (Fe₃O₄ and Fe₂O₃NiO₂ · H₂O) to specify the optimum conditions of immobilization. Removal of H2O2 and the properties of immobilized sets were also investigated. To that end, adsorption and then cross-linking methods onto magnetic particles were performed. The optimum immobilization conditions were found for catalase: immobilization time (15 min for Fe₃O₄; 10 min for Fe2O₃NiO₂ · H₂O), the initial enzyme concentration (1 mg/mL), amount of magnetic particles (25 mg), and glutaraldehyde concentration (3%). The activity reaction conditions (optimum temperature, optimum pH, pH stability, thermal stability, operational stability, and reusability) were characterized. Also kinetic parameters were calculated by Lineweaver-Burk plots. The optimum pH values were found to be 7.0, 7.0, and 8.0 for free enzyme, Fe₃O₄-immobilized catalases, and Fe₂O₃NiO₂ · H₂O-immobilized catalases, respectively. All immobilized catalase systems displayed the optimum temperature between 25 and 35°C. Reusability studies showed that Fe₃O₄-immobilized catalase can be used 11 times with 50% loss in original activity, while Fe2O₃NiO₂ · H₂O-immobilized catalase lost 67% of activity after the same number of uses. Furthermore, immobilized catalase systems exhibited improved thermal and pH stability. The results transparently indicate that it is possible to have binding between enzyme and magnetic nanoparticles.
本研究的目的是实现将过氧化氢酶固定在磁性粒子（Fe₃O₄ 和 Fe₂O₃NiO₂ · H₂O）上，以确定最佳固定化条件。还研究了过氧化氢的去除和固定化酶的性质。为此，进行了吸附和交联方法到磁性颗粒上。确定了过氧化氢酶的最佳固定化条件：固定化时间（Fe₃O₄ 为 15 分钟；Fe2O₃NiO₂ · H₂O 为 10 分钟）、初始酶浓度（1mg/mL）、磁性颗粒用量（25mg）和戊二醛浓度（3%）。对活性反应条件（最佳温度、最佳 pH 值、pH 值稳定性、热稳定性、操作稳定性和可重复使用性）进行了表征。还通过 Lineweaver-Burk 图计算了动力学参数。发现游离酶、Fe₃O₄ 固定化过氧化氢酶和 Fe₂O₃NiO₂ · H₂O 固定化过氧化氢酶的最佳 pH 值分别为 7.0、7.0 和 8.0。所有固定化过氧化氢酶系统的最佳温度均在 25-35°C 之间。可重复使用性研究表明，Fe₃O₄ 固定化过氧化氢酶可以使用 11 次，原始活性损失 50%，而 Fe2O₃NiO₂ · H₂O 固定化过氧化氢酶在相同次数的使用后失去 67%的活性。此外，固定化过氧化氢酶系统表现出改善的热稳定性和 pH 稳定性。这些结果清楚地表明，酶和磁性纳米粒子之间可以发生结合。
