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Chloro-Modified Magnetic Fe3O4@MCM-41 Core–Shell Nanoparticles for L-Asparaginase Immobilization with Improved Catalytic Activity, Reusability, and Storage Stability

Ulu, Ahmet, Noma, Samir Abbas Ali, Koytepe, Suleyman, Ates, Burhan
Applied biochemistry and biotechnology 2019 v.187 no.3 pp. 938-956
Fourier transform infrared spectroscopy, X-ray diffraction, asparaginase, catalytic activity, chemical composition, chemical structure, differential scanning calorimetry, differential thermal analysis, energy-dispersive X-ray analysis, immobilized enzymes, iron oxides, magnetic properties, magnetism, nanoparticles, pH, scanning electron microscopes, scanning electron microscopy, storage quality, temperature, thermogravimetry, zeta potential
This paper describes a new support that permits to efficient immobilization of L-asparaginase (L-ASNase). For this purpose, Fe₃O₄ magnetic nanoparticles were synthesized and coated by MCM-41. 3-chloropropyltrimethoxysilane (CPTMS) was used as a surface modifying agent for covalent immobilization of L-ASNase on the magnetic nanoparticles. The chemical structure; thermal, morphological, and magnetic properties; chemical composition; and zeta potential value of Fe₃O₄@MCM-41-Cl were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffraction patterns (XRD), and zeta-potential measurement. The immobilization efficiency onto Fe₃O₄@MCM-41-Cl was detected as 63%. The reusability, storage, pH, and thermal stabilities of the immobilized L-ASNase were investigated and compared to that of soluble one. The immobilized enzyme maintained 42.2% of its original activity after 18 cycles of reuse. Furthermore, it was more stable towards pH and temperature compared with soluble enzyme. The Michaelis–Menten kinetic properties of immobilized L-ASNase showed a lower Vₘₐₓ and a similar Kₘ compared to soluble L-ASNase. Immobilized enzyme had around 47 and 32.5% residual activity upon storage a period of 28 days at 4 and 25 °C, respectively. In conclusion, the Fe₃O₄@MCM-41-Cl@L-ASNase core–shell nanoparticles could successfully be used in industrial and medical applications.