title: [Dissolution enthalpies of DL-alpha-alanine and dipeptides of aliphatic series in aqueous solutions of KCl].
abstract: The integrated enthalpies of dissolution DeltasolH(m) of DL-alpha-alanine, DL-alpha-alanyl-glycine, DL-alpha-alanyl-beta-alanine, DL-alpha-alanyl-DL-alpha-alanine and L-alpha-alanyl-L-alpha-alanine in mixtures of water with KCl have been measured at concentrations of electrolyte up to 4 mole/kg (T=298.15 K). On the basis of the data obtained, the standard enthalpies of dissolution (DeltasolH(0)) and transfer (DeltatrH(0)) of the amino acids and dipeptides from water to aqueous solutions with KCl were determined. It was found that the dependences DeltatrH(0) = f(X2) for all systems have extreme character, which indicates different mode of interactions between the components of the solution in different ranges of electrolyte concentration. Within the framework of the formalism of the McMillan-Mayers theory, the enthalpic pair coefficients of interaction of hxy biomolecules with KCl estimated. The coefficients are discussed in terms of the integral enthalpic effects of interactions between the components in aqueous solutions and the structural features of solutes.
authors.forename: I N
authors.initials: IN
authors.lastname: Mezhevoĭ
authors.forename: V G
authors.initials: VG
authors.lastname: Badelin
mesh_terms: D000409:Alanine / Q000737:chemistry*; D002151:Calorimetry; D004151:Dipeptides / Q000737:chemistry*; D011189:Potassium Chloride / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D004151:Dipeptides; D012996:Solutions; D014867:Water; D011189:Potassium Chloride; D000409:Alanine