Abstract
The reversibility of the adsorption–desorption cycle was established by comparing the thermostability (determined by differential scanning calorimetry) and secondary structure (obtained by circular dichroism spectroscopy) of BSA before adsorption, adsorbed on, and exchanged from silica particles. Circular dichroism was also measured as a function of temperature at a given wavelength. Adsorbed BSA presents a higher thermostability and a lower α-helix content than the native protein while it regains its conformation when released from the surface back into the solution; the homomolecular exchange is reversible.The changes in ellipticity (at a given wavelength) as a function of the temperature show that the thermal denaturation of native, adsorbed, and exchanged BSA proceeds in two steps. For the dissolved protein, the first step up to 50°C involves a slight change in the structure while in the 50–90°C temperature range the actual unfolding takes place. For the adsorbed BSA, the first step proceeds up to 60°C and includes some intermolecular association between the adsorbed protein molecules, which may be responsible for the increased thermostability. The unfolding occurs in the 60–90°C range; it is less cooperative and involves a lower enthalpy change than the native protein. Adsorbed BSA presents the same secondary structure as that observed for dissolved BSA that has passed a heating–cooling cycle.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.