Monajati Maryam, Ariafar Nasim, Abedi Mehdi, Borandeh Sedigheh, Tamaddon Ali Mohammad
Department of Pharmaceutical Nanotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.
Center for Nanotechnology in Drug Delivery, Shiraz University of Medical Sciences, Shiraz, Iran.
Heliyon. 2024 Nov 1;10(21):e40072. doi: 10.1016/j.heliyon.2024.e40072. eCollection 2024 Nov 15.
The application of the amidohydrolase enzyme, L-asparaginase (ASNase), as a biocatalyst in the food and pharmaceutical industries has garnered significant interest. However, challenges such as hypersensitivity reactions, limited stability, and reusability under various operational conditions have hindered its cost-effective utilization. This paper introduces a novel nano-support for ASNase immobilization, namely the nanocomposite of iron oxide magnetic nanoparticles and amino acid-decorated graphene oxide (GO-Asp-FeO). Characterization using FTIR spectroscopy, FE-SEM, and TEM microscopy revealed the homogeneous distribution of iron oxide nanoparticles on the surface of GO sheets. The effects of carrier functionalization and carrier-to-protein ratio on the immobilization of ASNase were studied to optimize the immobilization conditions. The magnetized nanocomposite of ASNase exhibited a 4.4-fold lower Michaelis-Menten constant (Km), suggesting an enhanced affinity for the substrate. The immobilized ASNase demonstrated two to eight times higher thermostability compared to the free enzyme and showed an extremely extended pH stability range. Furthermore, the immobilized enzyme retained over 80 % of its initial bioactivity after eight repeated reaction cycles. These findings suggest that the immobilization of ASNase on GO-Asp- FeO nanocomposite could be a viable option for industrial applications.
酰胺水解酶L-天冬酰胺酶（ASNase）作为一种生物催化剂在食品和制药工业中的应用已引起广泛关注。然而，诸如过敏反应、稳定性有限以及在各种操作条件下的可重复使用性等挑战阻碍了其经济高效的利用。本文介绍了一种用于固定ASNase的新型纳米载体，即氧化铁磁性纳米颗粒与氨基酸修饰的氧化石墨烯的纳米复合材料（GO-Asp-FeO）。通过傅里叶变换红外光谱（FTIR）、场发射扫描电子显微镜（FE-SEM）和透射电子显微镜（TEM）进行的表征显示，氧化铁纳米颗粒均匀分布在氧化石墨烯片的表面。研究了载体功能化和载体与蛋白质比例对ASNase固定化的影响，以优化固定化条件。固定化ASNase的磁化纳米复合材料的米氏常数（Km）降低了4.4倍，表明对底物的亲和力增强。与游离酶相比，固定化ASNase的热稳定性提高了2至8倍，并且显示出极宽的pH稳定性范围。此外，固定化酶在八个重复反应循环后仍保留了超过80%的初始生物活性。这些发现表明，将ASNase固定在GO-Asp-FeO纳米复合材料上可能是工业应用的一个可行选择。
