The interaction of trypsin with one nanoparticle (CuO): Spectroscope identification

Enzymes hold a great promise as therapeutic agents because of their unique specificity and high level of activity. Conjugation of proteins to nanoparticles has numerous applications in imaging, sensing, catalysis, delivery, therapy and control of protein structure and activity[1,2]. Therefore, characterizing the nanoparticle–protein interface is of great importance. The effect of the interaction of nanoparticles with biological macromolecules e.g., enzyme is important in biological, industrial and pharmaceutical fields of research. Some inorganic nanoparticles have been shown to act as an enzyme inhibitor which may be connected to the change of the native enzyme structure. We report the binding of a serine protease (trypsin) as a model enzyme with CuO nanoparticles. To take a comprehensive evaluation of CuO nanoparticle effect, we investigated its interaction with a serine protease trypsin by multispectroscopic techniques. The result of absorption, circular dichroism and fluorescence techniques have been demonstrated the structural changes in secondary and tertiary structure of trypsin induced by binding of CuO nanoparticles. The changes in the structure of enzyme upon binding with nanoparticles are reflected through an increasing protease activity of trypsin-CuO nanoparticles complex in comparison to the absence of nanoparticles (pure enzyme). Also we showed that thermal stability of enzyme increased with increasing nanoparticles concentrations. The thermodynamic parameters for the trypsin -CuO nanoparticles binding interaction unveil the enthalpy as well as entropy driven binding (ΔH°<0 and ΔS°<0) with an overall favorable Gibbs free energy change (ΔG°<0). The thermodynamic parameters delineate the dominate role of hydrogen bond and van der Waals interaction in the binding process of CuO nanoparticles with trypsin[3]. Enzyme activity assay gave evidence at the functional aspect to clarify the fact that CuO nanoparticle could contribute to the conformational changes and furthermore alter the function of the enzyme.

کلیدواژه ها:

Trypsin ، Thermal stability ، activity ، Fluorescence ، CD