Comprehensive studies on the nature of interaction between catalase and SiO2 nanoparticle

The effect of SiO2 nanoparticle on the conformation and activity of catalase were studied and observed by UV–vis, circular dichroism, fluorescence spectroscopy and molecular modeling methods. All the experimental data showed that the spectral changes of catalase were induced by SiO2 nanoparticle exposure. SiO2 nanoparticle could bind to catalase by electrostatic, hydrogen bonding and hydrophobic forces. These interactions decreased the α-helices content of catalase, which had more unfolded and more flexible structure. These structural changes did not obviously affect the solvent polarity of environment around both Trp and Tyr residues on catalase. Moreover, the activity assay indicated that SiO2 nanoparticle was an activator for catalase activity. In a word, the biomolecular structure changes revealed by spectra provided a better understanding of the nanotoxicity and potential health effects of SiO2NP exposure.