PHYSICOCHEMICAL PROPERTIES OF PEPTIDES AND THEIR SOLUTIONS

Complex investigations of a series of dipeptides and their solutions in H2O were conducted by the methods of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), densimetry, and IR and Raman spectroscopy. The results of investigations by DSC and TGA show that the differences in the spatial structure of solid dipeptides of a homologous series sharply influences the character of phase transformations. Linear correlations between the values of the heat capacity of crystalline amino acids and peptides and the number of atoms, number and length of interatomic bonds. The dipeptides studied are classified into three groups: those with predominantly hydrophilic, those with predominantly hydrophobic and those with hydrophobic-hydrophilic (at different concentrations) characters of hydration in aqueous solutions. The ratio between hydrophilic and hydrophobic contributions to the hydration of dipeptides, and role of separate fragments of the molecules is considered. © 1990.