Study of Interactions between Amino Acids and Zinc Chloride in Aqueous Solutions through Volumetric Measurements at T = (288.15 to 318.15) K

Abstract

Densities, F, of glycine, DL-R-alanine, DL-R-amino-n-butyric acid, L-valine, and L-leucine in aqueous and in mixed aqueous solutions of zinc chloride, (0.1, 0.5, 1.0, and 1.5) mol • kg -1 , have been determined by using a vibrating-tube digital densimeter at (288.15, 298.15, 308.15, and 318.15) K. These data have been used to calculate the apparent molar volumes, V 2,φ , of the studied amino acids. The partial molar volumes, V 2 0 , at infinite dilution are evaluated and further used to obtain the corresponding transfer volumes, ∆ t V 0 for amino acids from water to aqueous zinc chloride solutions. Partial molar expansibilities, V 0 E , hydration numbers, n H , interaction coefficients, and side chain group contributions of amino acids have also been calculated. The ∆ t V 0 values for the studied amino acids are positive, and these values increase with an increase in the concentration of zinc chloride as well as with temperature. The parameters obtained from the volumetric study are used to understand various mixing effects due to the interactions between amino acids and zinc chloride in aqueous solutions.

Volumetric interactions of a series of α-amino acids in aqueous magnesium chloride solutions at 278.15, 288.15, 298.15, and 308.15 K

“…The partial molar expansions calculated in this work are in high accordance to those measured by Mota et al [1] and Martins et al [2]. The same approach was applied to the data published by Martins et al [2], Yan et al [10], Shen et al [11], and Banipal et al [12], for DL-alanine and Lark et al [7], for L-alanine, allowing the comparison in Fig. 1a.…”

“…The dehydration of the amino acids increases both with salt molality and temperature. The decrease in the hydration number becomes progressively smaller as the hydrophobic part of amino acids increases, a feature already observed in several works [1,2,12]. The data measured in this work can be used to compare the dehydration effect of magnesium chloride to that of ammonium sulfate [1,2].…”

“…For all amino acids, the magnitude of the dehydration, represented as the difference (Dn H ) between the hydration numbers of the amino acid in pure water at 298.15 K to those in an aqueous solution containing an electrolyte with 1 molal concentration at the same temperature, is higher in the presence of (NH 4 ) 2 SO 4 . Considering only the anion, that is expected since we [11]; (closed circle) Banipal et al [12]; (open square) Cabani et al [13]. b L-Threonine (open diamond) this work; (X) Mota et al [1]; (open circle) Hakin et al [16]; (open square) Cabani et al [13]; (closed circle) Mizuguchi et al [17].…”

Interactions of L-Aspartic Acid with Aqueous Solution of 1,2-Propanediol at Different Temperatures: A Volumetric, Compressibility and Viscometric Approach

“…Therefore, the feasible approach is to investigate interactions of the model compounds of proteins, e.g., amino acids, in aqueous and mixed-aqueous solutions. [1][2][3][4][5][6] The choice of water for preparing mixed solvent stems from its important and unique role in determining the structure and stability of protein. Its presence also gives rise to hydrophobic forces, which are of prime importance in stabilizing native globular structure of protein.…”

Thermo-Acoustical Studies on Interionic Interactions of Some -amino Acids in Aqueous Sucrose Solution at Varying Mass Percentages

“…one useful approach is to investigate interactions of the model compounds of proteins, i.e., amino acids in aqueous and mixed-aqueous solution [1][2][3][4][5] . The physicochemical properties of amino acids in aqueous solutions provide valuable information on solute-solute and solute-solvent interactions that are important in understanding the stability of proteins, and are implicated in several biochemical and physiological processes in a living cell 6 .…”