Calorimetric studies of interactions between simple peptides and electrolytes in water at 298.15 K

Abstract

The standard molar enthalpies of solution at infinite dilution Δ solH m ∞ of glyclyglycine, glycylglycylglycine and DL-alanyl-DL-alanine in aqueous solutions of sodium chloride and sodium iodide have been determined by calorimetry at the temperature 298.15 K. The results obtained were used to calculate the heterotactic enthalpic interaction coefficients h xy of peptide with the salts in water. The effect of the ion type and of the peptide fragment number peptide with the salts in water. The effect of the ion type and of the peptide fragment number on the magnitude of the interaction parameter is discussed. The group contributions illustrating the interactions between the electrolytes (NaCl or NaI) and CH 2, “pep” and “ion” groups in the peptide molecules were determined and analysed.