The effect of solvated ions on the thermal denaturation of human serum albumin in water-dimethylsulfoxide solutions

The effects of solvated ions on the thermal denaturation of human serum albumin (HAS) in water-dimethylsulfoxide (DMSO) solutions were studied by the method of electron absorption spectroscopy. It was shown that depending on the DMSO concentration, electrolytes (LiCl, LiNO₃, LiClO₄, NaCl, and NaNO₃) contained in these solutions were characterized by different anion and cation solvation degrees: unlike cations, anions were only negligibly solvated, which affected HAS thermal denaturation. Electrostatic interactions between anions and positively charged amino acid residues supporting protein denaturation subsided in the line Cl⁻ > NO₃⁻ > ClO₄⁻.