PARTIAL MOLAR VOLUMES, EXPANSIBILITIES, AND COMPRESSIBILITIES OF ALPHA,OMEGA-AMINOCARBOXYLIC ACIDS IN AQUEOUS-SOLUTIONS BETWEEN 18 AND 55-DEGREES-C

We have determined the apparent molar volumes, expansibilities, and adiabatic compressibilities of a homologous series of eight alpha,omega-aminocarboxylic acids within the temperature range 18-55-degrees-C. We interpret the resulting data in terms of the hydration of the component aliphatic and charged atomic groups. From temperature-dependent studies, we find the total electrostriction of the noninteracting amino and carboxyl groups at 25-degrees-C to be equal to -26 cm3 mol-1. We also evaluated the temperature dependences of both the density and the coefficient of adiabatic compressibility and interpreted these data in terms of hydrophobically and electrostatically perturbed solvent domains in the hydration shells of the aliphatic and charged atomic groups. We discuss the implications of our results for developing an understanding of the forces that stabilize/destabilize biologically important structures.