Interaction between Uracil and L-Histidine in an Aqueous Buffer Solution in the 288.15–313.15 K Range of Temperatures

• Published in: Russian Journal of Physical Chemistry A 2021-11, Vol.95 (11), p.2254-2262
• Main Author: Tyunina, E. Yu
• Format: Article
• Language: English
• Subjects: Amino acids; Buffer solutions; Chemistry; Chemistry and Materials Science; Histidine; Ions; Physical Chemistry; Physical Chemistry of Solutions; Uracil
• ISSN: 0036-0244; 1531-863X
• DOI: 10.1134/S0036024421110248

Densimetry and differential scanning calorimetry are used to study interactions between uracil (Ura) and the heterocyclic amino acid L-histidine (His) in an aqueous buffer solution (рН 7.4). Experimental values of the density and specific heat capacity of uracil in aqueous buffer solution and aqueous buffer solution with the amino acid are obtained in the 288.15–313.15 K range of temperatures. The concentration of Ura is varied from 0.004 to 0.032 mol kg −1 at a constant His concentration (0.0125 mol kg −1 ). The apparent molar parameters of uracil ( φ V Ura , ϕ C p ) in aqueous buffer solution and the aqueous buffer solution containing the amino acid are determined. It is shown the interaction between His and Ura is accompanied by the formation of a molecular complex. It is found that the partial molar properties ( , ) of the transfer of uracil from the aqueous buffer solution to the aqueous buffer solution with the amino acid have positive values in the investigated range of temperatures. The results are discussed in the context of Gurney’s model.