The Effect of TiO2-Nanoparticle on the Activity and Stability of Trypsin in Aqueous Medium

Trypsin (E.C.3.4.21.4) is a serine protease commonly used in proteomics for digestion of proteins. In the present study, the effect of nano-TiO2 on the conformation and catalytic activity of trypsin were studied. The thermal denaturation of trypsin has been investigated in the presence and absence of nano-TiO2 over the temperature range (293-373 K) at pH 3.0 and 7.25, using temperature scanning spectroscopy. In presence of nani-TiO2, the ester lytic activity of trypsin is decreased. The result indicates that Nano-TiO2 is a non-competitive inhibitor for enzyme trypsin. With the addition of TiO2 to protein solution at pH 3.0, the maximum intensity of emission spectrum of trypsin is increased. But at pH 7.25, the maximum intensity of emission spectrum of trypsin is decreased. The result of fluorescence spectroscopy indicated that the structure of the Trp residue environments was altered. Increasing the concentration of nano-TiO2 decreases the stability of trypsin to thermal denaturation.