Raman spectroscopy of protein–water interactions in aqueous solutions

Abstract

Some conclusions about the effect of protein presence on water structure, as found by Raman spectroscopy, are presented here. An overall intensity decrease and strong spectral shape changes which are encountered in the OH stretching region when increasing protein concentration are explained in terms of a water model taking into account three water species with different Raman efficiency. The hydration value of protein is calculated and results are an order of magnitude greater than those previously reported. A simple model of protein water interaction is formulated to explain the presence of a quasitransition point in OH stretching intensity when varying concentrations. Correlation is made with calorimetric data.