Thermodynamics of dipeptides in water. VI. Calorimetric determination of enthalpy changes of dissociation processes in water of the free α-carboxyl and α-amino groups in a series of dipeptides. Comparison of these processes for two series of dipeptides

Abstract

A calorimetric study has been made on the dissociation processes in water of the free α-amino group of the amino terminal residue and the free α-carboxyl groups of the carboxyl terminal residue in a series of dipeptides having valine as first common term. These values have been compared with those of the proton dissociation processes related to the same groups of the corresponding single α-amino acids. The results of this series have also been considered in relation to those from another series of dipeptides, previously studied, in an effort to compare the effects of different chains on the dissociation processes of the free α-carboxyl and free α-amino groups.