Aqueous solutions containing amino acids and peptides. Part 12.—Enthalpy of interaction of α-alanine, α-aminobutyric acid, norvaline and norleucine with sodium chloride at 298.15 K

Abstract

A microcalorimetric method has been used to obtain the pairwise enthalpy of interaction coefficients for the amino acids α-alanine, α-aminobutyric acid, norvaline and norleucine with sodium chloride in aqueous solutions at 298.15 K. The results obtained were combined with previously determined free energy coefficients to obtain the corresponding entropy coefficients. It is found that each of the thermodynamic parameters become more positive as the hydrocarbon chain is increased in length and they eventually reach constant values.