Search

Integral enthalpies of solution Δ H of diglycylglycine in aqueous solutions of glycerol, ethylene glycol, and 1,2-propylene glycol are measured via solution calorimetry. The experimental data are used to calculate the standard enthalpies of solution (Δ H°) and transfer (Δ H°) of the tripeptide from water to aqueous solutions of polyatomic alcohols. The enthalpic pairwise coefficients h of interactions between the tripeptide and polyatomic alcohol molecules are calculated using the McMillan-Mayer solution theory and are found to have positive values. The findings are discussed using the theory of estimating various types of interactions in ternary systems and the effect the structural features of interacting biomolecules have on the thermochemical parameters of diglycylglycine dissolution. [ABSTRACT FROM AUTHOR]

Integral enthalpies of dissolution Δ H of DL-valine are measured via calorimetry of dissolution in aqueous solutions of glycerol, ethylene glycol, and 1,2-propylene glycol. Standard values of the enthalpies of dissolution (Δ H) and transfer (Δ H) of amino acid from water to mixed solvent are calculated from the resulting experimental data. The enthalpy coefficients for pair interactions h of amino acid with polyatomic alcohol molecules are calculated using the McMillan-Meyer theory and have positive values. The obtained results are discussed in light of the theory of the predomination of various types of interactions in mixed solutions and the effect of structural features of interacting biomolecules on the thermochemical parameters of the dissolution of amino acids. [ABSTRACT FROM AUTHOR]

The vaporization enthalpy of polyatomic alcohols with different structures under normal conditions is calculated using a modified Randič method. The vaporization enthalpy of polyatomic alcohols is shown to largely depend on the number of hydrogen bonds formed by alcohols. [ABSTRACT FROM AUTHOR]