Thermodynamic Characteristics of Acid–Base Reactions in Aqueous Solutions of DL-α-Alanyl-DL-norleucine

Abstract

The heat effects of the interaction between a solution of DL-α-alanyl-DL-norleucine and solutions of HNO₃ at different pH values at 288.15 and 308.15 K and ionic strength values of 0.5, 1.0, and 1.5 (background electrolyte, KNO₃) are measured via calorimetry. The heat effects of the stepwise dissociation of the dipeptide are determined. Standard thermodynamic characteristics (Δ_rH°, Δ_rG°, Δ_rS°, and \(\Delta C_{p}^{^\circ }\)) of the reactions of acid–base interaction in aqueous solutions of DL-α-alanyl-DL-norleucine are calculated. The relation between the thermodynamic characteristics of the dissociation of a dipeptide with the structure of this compound is considered.