Amino Acid Solvation in Aqueous Kosmotrope Solutions: Temperature Dependence of the L-Histidine-Glycerol Interaction

Kustov, Andrey V. and Smirnova, Nataliya L. and Neueder, Roland and Kunz, Werner (2012) Amino Acid Solvation in Aqueous Kosmotrope Solutions: Temperature Dependence of the L-Histidine-Glycerol Interaction. JOURNAL OF PHYSICAL CHEMISTRY B, 116 (7). pp. 2325-2329. ISSN 1520-6106,

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Abstract

We have studied thermodynamics of interaction between the aromatic amino acid L-histidine and glycerol, which is one of the most important stabilizing agents for proteins in water. The pair and triplet interaction parameters have been extracted from enthalpy and solubility data using standard thermodynamic manipulations in a wide temperature range. Our results indicate for the first time that the L-histidine-glycerol pair and triplet interactions are characterized by rather small enthalpy and entropy changes, which do not depend on temperature in either cold or hot water. These temperature-independent enthalpies and entropies of interaction lead to zero heat capacity changes during the amino acid transfer from water to both dilute and rather concentrated aqueous glycerol solutions. We attribute this behavior to a delicate balance between contributions from hydrophobic and hydrophilic fragments in the solute molecules. This unique feature appears to be the major reason that thermodynamics of pair and triplet interactions are nearly identical at standard and physiological temperatures.

Item Type: Article
Uncontrolled Keywords: ETHYLENE-GLYCOL; 298.15 K; 1,2-PROPYLENE GLYCOL; UREA SOLUTIONS; WATER; ENTHALPIES; MIXTURES; AMIDE; PHENYLALANINE; 25-DEGREES-C;
Subjects: 500 Science > 540 Chemistry & allied sciences
Divisions: Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > Prof. Dr. Werner Kunz
Depositing User: Dr. Gernot Deinzer
Date Deposited: 19 May 2020 07:03
Last Modified: 19 May 2020 07:03
URI: https://pred.uni-regensburg.de/id/eprint/19219

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