Influence of isoleucyl dipeptide side-chains on the dissociation and intermolecular interactions in water at 298.15 K

Enthalpies of dissociation of four isoleucyl dipeptides having alkyl side-chains (l-isoleucine-glycine, l-Ile-Gly; l-isoleucine-l-alanine, l-Ile-l-Ala; l-isoleucine-l-valine, l-Ile-l-Val; l-isoleucine-l-isoleucine, l-Ile-l-Ile) in water at 298.15 K have been determined. Enthalpies of dilution have also been calculated. These results were used to derive the enthalpic coefficients of interactions according to the modified McMillan–Mayerʹs model. The results are considered in an effort to establish a possible relation between dissociation, intermolecular interactions and the size of the alkyl side-chains.