The temperature dependence of the pair and triplet interaction between aromatic amino acid L-Tryptophan (Trp) and glycerol (Gl) or urea (U) in an aqueous medium was studied. For this goal, the enthalpies of solution of Trp in the water-Gl and water-U mixtures were determined in the temperature range of 298.15–328.15 K. The heat capacity values of amino acid solution as well as the partial molal heat capacities were calculated. The virial enthalpic coefficients of pair (Gl–Trp or U–Trp) and triple (Gl–Gl–Trp or U–U–Trp) interactions in aqueous solution were also computed in terms of the excess function concept. The results obtained were used to analyze the solute-non-electrolyte interactions in a liquid phase and their possible influence on stability of protein macromolecules.
