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Updated: Sep 20, 2025

Solubility of Hydrophobic Compounds in Aqueous Solution Using Combinations of Self-assembling Peptide and Amino Acid
Published on: September 20, 2017
Affinity of aromatic amino acid side chains in amino acid solvents
Akira Nomoto1, Suguru Nishinami1, Kentaro Shiraki1
1Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
Abstract:
The affinity between amino acid and water is important for understanding how proteins behave in aqueous solutions. For example, the hydrophobicity of amino acid side chains determines a protein's solubility. However, the affinity of amino acid side chains in amino acid solvents should be determined in order to understand the propensity of protein condensates induced by multivalent amino acid interactions. Here we measured the transfer free energy of amino acid side chains (ΔGSC) from water to amino acid solvents. The ΔGSC of aromatic amino acids showed a different value depending on the type and the pH of amino acid solvent. Interestingly, the propensity of ΔGSC was completely different from the hydrophobicity of amino acids. This indicate that the ΔGSC describes the affinity between amino acid side chains involving the existence of water. The ΔGSC is a significant parameter for understanding whether amino acid side chains prefer bulk or protein condensate.
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