Abstract
AbstractBovine serum albumin (BSA), a highly complex protein, plays important functions in immunology analysis and food science. In the denaturation study of proteins, heat treatments are frequently required for a variety of purposes and they can change the physical, chemical, biological and functional properties of proteins. Therefore, during thermal processing to understand, monitor, and control protein changes, particularly unfolding and refolding are important. There are many methods to detect the structures of protein, such as electrophoresis, X-ray diffraction crystallography, circular dichroism. However, these methods are not easy to monitor the denaturation process of BSA in real time.In this study, we have built up an optical heterodyne polarimeter capable of 12.8-fold of amplification factor in measuring the optical rotation angle and then understand the structure changes of protein. BSA under heat treatment can proceed structure changes. We observed thermal denaturation of BSA by measuring the real-time changes of optical rotation angle and transmission power, and then used electrophoresis to verify the results. For 2.5% (g/ml) BSA solution, the results indicate that BSA begins to denature at 66℃ and then soon goes to an unknown state which can restore the optical rotation angle. The denatured state is a reversible process. When the temperature goes beyond 68℃, BSA solution begins an irreversible aggregation state.