THE SOLUBILITIES OF 5 CYCLIC DIPEPTIDES IN WATER AT THE TEMPERATURE 298.15-K

The solubilities of five cyclic dipeptides: c-(glycylglycine), c-(L-al anylglycine), c-(L-alanyl-L-alanine), c-(L-valyl-L-valine), and c-(gly cyl-L-leucine), in water at the temperature 298.15 K have been redeter mined using an improved technique. The solubility constants of the dip eptides were used to calculate molar Gibbs free energies of dissolutio n. Also, the molar enthalpies of dissolution and the corresponding hea t-capacity changes previously determined in our laboratory were re-eva luated from the new solubility constants. Finally, from the molar enth alpies and the Gibbs free energies of dissolution, the corresponding m olar entropies of dissolution of the dipeptides were calculated.