THERMODYNAMIC PROPERTIES OF PEPTIDE SOLUTIONS .15. PARTIAL MOLAR ISENTROPIC COMPRESSIBILITIES OF SOME GLYCYL DIPEPTIDES IN AQUEOUS-SOLUTIONAT 15 AND 35-DEGREES-C

The partial molar isentropic compressibilities at infinite dilution, K -s,2(o), have been obtained for eight glycyl dipeptides of sequence gl y-X (X is an amino acid) in aqueous solution at the temperatures 15 an d 35 degrees C. The results have been combined with those obtained at 25 degrees C, that were reported earlier, to evaluate the temperature dependences of K-s,2(o) for the dipeptides in the temperature range 15 to 35 degrees C. The K-s,2(o), values for all the dipeptides are nega tive and increase (become more positive) with an increase in temperatu re. The slopes of the temperature dependences of K-s,2(o) for the dipe ptides with typically hydrophobic side-chains are significantly larger than those for dipeptides with hydrophilic side-chains.