Institution Of The Thesis: Gazi University, Turkey
Approval Date: 2018
Thesis Language: Turkish
Student: Jehad Daana
Consultant: HAYRETTİN TÜMTÜRKAbstract:
In recent years, noticeable achievements have been spent in the development of magnetic nanoparticles (MNPs). Enzymes ability to catalyze reactions and engage in complex syntheses has long made them attractive for use in a multitude of industrial, and research applications. This work presents the synthesis and uses surface modified magnetite nanoparticles for the covalent attachment of γ-Glutamyl transpeptidase enzyme. γ-Glutamyl transpeptidase (γ-GGT; EC 18.104.22.168) is an enzyme that catalyzes the transfer of the γ-glutamyl group of glutathione to an amino acid or a peptide. The activity of GGT is a critical indicator for liver function. In addition, it is used as a biochemical marker for alcohol consumption because there is a direct relationship between alcohol intake and the activity of GGT. Fe3O4 MNPs were prepared via well-known co-precipitation reaction. Subsequently, the surface of magnetic nanoparticles was modified by employing a plant-derived polyphenol (rich with hydroxylic groups) tannic acid as the structure-directing agent as well as the stabilize to enhance the ability to immobilize GGT covalently. GGT was covalently immobilized on tannic acid modified MNPs after exposing nanoparticles to pH 9,2. Enzyme loading was 92,98% onto the MNPs. The immobilized enzyme demonstrated maximum catalytic activity at pH 8,5 and 60 °C. The kinetic parameters of free and immobilized enzyme were evaluated according to the LineweaverBurk plot. The properties of Fe3O4 and its modified forms were examined by Fourier transform infrared spectroscopy (FTIR), UV-vis spectrometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM).