Self-assembling of glutathione in aqueous environment: A combined experimental and theoretical study

Abstract

Detailed concentration-dependent measurements of transient and stationary ultrasonically induced birefringence were combined with molecular docking and DFT techniques to study the formation of glutathione (GSH) self-aggregates in aqueous solutions. Molecular docking revealed the formation of dimers through hydrogen bonding with a binding free energy equal to −3.44 kcal/mol. The behavior of stationary birefringence measurements with concentration allowed us to assign the observed relaxation process to self-association mechanism between glutathione molecules. Systematic analysis of the birefringence traces in the transient region permitted the evaluation of the orientational relaxation times and the corresponding hydrodynamic volumes. Combining the concentration dependent spectroscopic data with supplementary measurements of several physical properties, such as mass density, shear viscosity, sound speed, isentropic compressibility, specific conductivity, and pH, the self-association scheme has been established. The chemical reactivity and the biological activity of the GSH monomer and dimer species were also evaluated and discussed in the context of the fair competence of GSH molecules to interact forming aggregates in aqueous environment.