Recently, understanding of the interaction of proteins with various nanomaterials has grown. The protein corona can detect not only how nanoparticles interact with cells but their biological effects and toxicity too. Structural and optical properties of the titanium dioxide nanoparticles (TiO2NPs) have been investigated using (UV-Vis) spectroscopy and Scanning Electron Microscope (SEM). The effect of TiO2 NPs on salivary peroxidase activity was studied kinetically. The results in this study indicated that salivary peroxidase activated by TiO2 NPs. the Vmax and Km for enzyme activity without nanoparticles were (133.33)U/L, and (0.133)mol/L respectively, and (714.3)U/L, (0.357)mol/L in the presence of TiO2NPs.