The Size Effect of Superparamagnetic Iron Oxide Nanoparticles on Hen Egg-White Lyzozyme Structure and Activity

Document Type : Research Article


1 Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran

2 Department of Chemistry, Razi University, Kermanshah 67149-67346, Iran

3 Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran


Superparamagnetic iron oxide nanoparticles (SPIONs) with Fe3O4 molecular composition were taken into consideration for protein interactions and drug delivery study. Regarding SPIONs in nanomedicine and drug delivery systems, investigation on the interaction between SPION and a model protein and structural and functional changes could be insightful. SPIONs with 20, 50 and 100 nm size were chosen. UV-visible spectroscopy study showed a protein-nanoparticle interaction. Circular dichroism was used in order to measure changes in the secondary structure of lysozyme in interaction with SPIONs and showed a remarkable decrease in helical structures of the protein. Quenching analysis was employed in order to understand the essence of interaction. SPIONs and lysozyme interaction show a combination of dynamic and static quenching. Activity and enzymatic properties of SPIONs bonded lysozyme were measured in comparison with free lysozyme. Activity decreased notably in every size of SPIONs, but Km has changed in under the influence of different reaction conditions.


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