Transport properties of Gamma-Aminobutyric Acid in water

In the present work, molecular dynamics study of diffusion of Gamma Aminobutyric acid in water at different temperatures 298.2 K, 303.2 K, 313.2 K, 323.2 K, 333.2 K have been performed. The solute and solvent is modeled using OPLS AA platform. The structure of the system is analyzed using RDF of different atom or molecule pairs. In all the cases, at least two or more peaks were obtained which suggests appreciable amount of interaction between atoms and molecules. The self diffusion coefficient of GABA and water is calculated from mean square displacement (MSD) plot using Einstein's relation. Binary diffusion coefficient is obtained from self diffusion coefficient using Darken's relation. Binary diffusion coefficient agrees well with the previously reported experimental data within an error of around 7%. The temperature dependence of self diffusion coefficients of GABA in water follows the Arrhenius behaviour. With the help of Arrhenius plot, we estimate the activation energy. The activation energy of water agrees well with the previously reported experimental data within an error of around 17%.