Partial molar heat capacities of the side chains of some amino acid residues in aqueous solution. The influence of the neighboring charges.

Partial molar heat capacities of the side chains of some amino acid residues (Ala, Val, Leu, Ile, Ser) have been determined over a broad temperature range from calorimetric heat capacity measurements of the corresponding tripeptides and cyclodipeptides. The data obtained are compared with those determined earlier from the heat capacities of analog compounds. It is shown that in amino acids and even tripeptides of the Gly-X-Gly type, the influence of the end charges on the heat capacity of the side chain is rather significant even in buffered solutions of high ionic strength.