The partial molar enthalpies in aqueous solution of some amino acids with polar and non-polar side chains

Abstract

The enthalpies of dilution of aqueous solutions of L-alanine, L-arginine, L-cysteine, glycine, L-serine, and L-valine have been measured by flow calorimetry, and used to calculate the partial molar enthalpies of the solution components. Partial molar entropies of water in the solutions were calculated using literature data for the activity of H 2O in the solutions. The partial molar enthalpies of H 2O in the solutions of amino acids with non-polar side chains were negative but in the solutions of amino acids with polar side chains and in glycine solutions they were positive.