Thermodynamic properties of peptide solutions. Part 15. Partial molar isentropic compressibilities of some glycyl dipeptides in aqueous solution at 15 and 35°C

The partial molar isentropic compressibilities at infinite dilution,K_s,2^o, have been obtained for eight glycyl dipeptides of sequence gly-X (X is an amino acid) in aqueous solution at the temperatures 15 and 35°C. The results have been combined with those obtained at 25°C, that were reported earlier, to evaluate the temperature dependences ofK_s,2^o for the dipeptides in the temperature range 15 to 35°C. TheK_s,2^o values for all the dipeptides are negative and increase (become more positive) with an increase in temperature. The slopes of the temperature dependences ofK_s,2^o for the dipeptides with typically hydrophobic side-chains are significantly larger than those for dipeptides with hydrophilic side-chains.