Partial molar adiabatic compressibilities of transfer of some amino acids from water to aqueous lactose solutions at different temperatures

Abstract

Apparent molar adiabatic compressibilities ( K ϕ, s ) of glycine, L-alanine, L-valine, and L-leucine have been determined in aqueous and mixed aqueous solutions of lactose (2 to 6 mass%) at T = (293.15, 298.15, 303.15, and 308.15) K. From these data partial molar adiabatic compressibilities at infinite dilution ( K ϕ, s 0) have been evaluated to calculate corresponding transfer function. The transfer partial molar adiabatic compressibilities at infinite dilution ( ΔK ϕ, s 0) are found to be positive. The decrease in the magnitude of transfer partial molar adiabatic compressibilities from glycine to L-leucine indicates the dominance of hydrophobic–hydrophobic interactions between the increasing side chains of amino acids. Also, the contributions of NH 3 + COO − , and CH 2 groups have been calculated by the linear correlation of K ϕ, s 0 with number of carbon atoms in the alkyl chain of amino acids.