Mardin Artuklu University, Vocational High School of Health Services, 47100 Mardin, Turkey; Department of Genetics and Bioengineering, Yeditepe University, Atasehir, Istanbul 34755, Turkey.
Department of Chemistry, Faculty of Science & Arts, Inonu University, Malatya 44280, Turkey.
Int J Biol Macromol. 2020 Jan 1;142:443-451. doi: 10.1016/j.ijbiomac.2019.09.116. Epub 2019 Oct 5.
In this study, maltose-functionalized magnetic core/shell nanoparticles (FeO@Au NPs) as a promising carrier matrix for a simple and effective immobilization of l-asparaginase (l-ASNase) were prepared and characterized using imaging techniques including atomic force microscopy (AFM) and transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The results indicate that the NPs are monodispersed with an average diameter of 10 nm and magnetization of 9.0 emu g. Under the optimal conditions, 77.2 ± 2.3% of the total l-ASNase was immobilized. It was found that the acid-base tolerance and thermal stability of immobilized l-ASNase were significantly improved in comparison to the free form of the enzyme in solution. For instance, while only 10% of the immobilized enzyme was lost its activity, the free form was lost its activity more than 50% after 3 h incubation at 55 °C. After 13 times recycling, the immobilized l-ASNase retained about 50% of its initial activity. Moreover, the free and immobilized l-ASNase maintained their initial activities about 25 and 64% after 28 days storage at 25 °C, respectively. Km value of immobilized l-ASNase decreased to 1.59 from 2.95 mM as an indication of increased enzyme affinity for the substrate. The results of this study suggest that the maltose-coated magnetic nanoparticles are excellent nanovehicles to carry enzymes for a range of industrial applications.
在这项研究中，制备了麦芽糖功能化的磁性核/壳纳米粒子（FeO@Au NPs）作为一种有前途的载体基质，用于简单有效地固定 L-天冬酰胺酶（L-ASNase），并通过原子力显微镜（AFM）、透射电子显微镜（TEM）和振动样品磁强计（VSM）等成像技术对其进行了表征。结果表明，纳米粒子呈单分散性，平均直径为 10nm，磁化强度为 9.0 emu g。在最佳条件下，77.2±2.3%的总 L-ASNase被固定。结果发现，与溶液中游离酶相比，固定化 L-ASNase 的酸碱耐受性和热稳定性显著提高。例如，固定化酶只有 10%失去活性，而游离酶在 55°C孵育 3 小时后，其活性损失超过 50%。经过 13 次循环后，固定化 L-ASNase 保留了约 50%的初始活性。此外，游离和固定化的 L-ASNase 在 25°C下储存 28 天后，分别保持其初始活性的约 25%和 64%。固定化 L-ASNase 的 Km 值从 2.95mM 降低到 1.59mM，表明酶对底物的亲和力增加。本研究结果表明，麦芽糖包覆的磁性纳米粒子是一种优良的纳米载体，可用于一系列工业应用中的酶载。
