STUDY ON THE ACTIVITY-COEFFICIENTS AND THE SOLUBILITIES OF AMINO-ACIDS IN WATER BY THE PERTURBATION-THEORY

A non-primitive perturbation model for chain-like molecules has been u sed to correlate the activity coefficients of amino acids and peptides in aqueous solution. In this model, the mixed segments of hard sphere s are taken as the reference and the chain formation, the dipole-dipol e and L-J interactions are taken as the perturbation terms. The equati on can accurately correlate the activity coefficients of amino acids a nd peptides in water with four parameters. The solubilities of amino a cids in pure water between 0-100 degrees C can be predicted with the m odel parameters, and the experimental values of standard entropy and e nthalpy changes in the dissolving process. (C) 1998 Elsevier Science B .V.