Comparative Studies on the Interaction of ‎Proteinase-K with Fe2O3, Fe3O4 and SiO2 ‎Nanoparticles

Document Type : Research Paper


1 Department of Biology, University of Shahrekord, P.O. Box: 115, Shahrekord, I. R. of ‎Iran.‎

2 Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box 87317-‎‎51167, Kashan, I. R. Iran.‎


   The interaction of Fe2O3, Fe3O4 and SiO2 nanoparticles with proteinase K activity was investigated using UV–vis spectroscopy. Proteinase K EC ( is a member of serine protease family, which is produced from fungus Tritirachum album Limber.The effects of nanoparticles on proteinase K activity were studies at 40˚C in pH 7.0 using sodium phosphate as buffer. It was found that in the presence of nano-Fe2O3 and nano-Fe3O4, Vmax was decreased but Km was constant. This results indicated that nano-Fe2O3 and nano-Fe3O4 acted as noncompetitive inhibitors. In the presence of nano-SiO2 the amount of Km increased but Vmax decreased, that showed nano-SiO2 acted as a mixed inhibitor. The dissociation constant (Ki) value for binding nano-Fe2O3, nano-Fe3O4 to proteinase K was equal to 11µM and 8.5µM respectively that indicated the binding of nano-Fe3O4 to the enzyme was stronger than nano-Fe2O3. The KI and Ki value for nano-SiO2 was 22.5µM and 8µM respectively.


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