Enthalpies of solution of glycine, L-alanine, L-serine, L-threonine, diglycine, and triglycine were measured in water and aqueous solutions of D-mannitol, D-sorbitol and inositol at 298.15 K by an RD-496 II microcalorimeter. Enthalpies of transfer of these amino acids and glycine peptides from water to aqueous polyol solutions were calculated. It was shown that the enthalpies of transfer had negative values in the investigated concentration range, and decreased with increasing the concentration of polyol. The interactions of the amino acid or glycine peptide molecules with polyol molecules were analyzed and explained from the co-sphere model.

Key words: enthalpy of solution, enthalpy of transfer, amino acid, glycine peptide, polyol