Thermodynamic studies of transfer of some amino acids and peptides from water to aqueous glucose and sucrose solutions at 298.15 K

Abstract

Partial molar heat capacities and volumes for a homologous series of amino acids and dipeptides have been measured in aqueous 1 mol kg^–1 glucose and sucrose solutions at 298.15 K using flow microcalorimetry and densimetry, respectively. These data have been utilized, in conjunction with the data obtained for them in water earlier, to deduce the partial molar heat capacities and volumes of transfer from water to 1 mol kg^–1 aqueous glucose and sucrose solutions. A comparison of these transfer parameters with similar ones in aqueous sodium chloride and calcium chloride solutions is made. The results are explained using the cosphere overlap model and the factors governing the stability of proteins in these sugar solutions have been discussed.