Response of ovalbumin to fructose addition and pH variations-ultrasonic and FTIR study.

Resumo

Main aim of this work is to understand how the protein ovalbuminis affected by thepresence of cosolvent and variations in pH of the medium.The addition of cosolventin many cases is found to control the extent of denaturationand pH is one of the main sources of denaturant of proteins. In this work, keeping fructose solution as cosolventand pH ofthe solution as main variable, the extent of denaturation is analysed by ultrasonic methods and are further confirmed by FTIR amide-I second derivative spectraat 303 K. Obtained results showsthat denaturation is sensitive to pH, however, acidic and alkaline behave totally in a different way. It was found that the impact of alkaline pH produces lesser denaturation and isslower whereas the impact of acidic pH,though poor,isspecific and instantaneous.Ultrasonic analysis shows that pH variationcandenaturethe protein whereas the addition of cosolvent supports renaturation. FTIR spectra were recorded for the experimental samples from which the second derivative curve fitted spectra were constructed using Origin program. Quantitative assignment of peaks and the variations in cumulative areas calculated for the structures like α-helix, β-sheets etc confirms the observations of ultrasonic analysis that the pH variations aid in denaturation whereas the cosolvent supports the renaturation of protein.