Physico-chemical studies of intermolecular interaction in biological / biochemical systems

Abstract

Ultrasound velocity (u), density (and#61554;) and viscosity coefficient (and#61544;) values have been measured for ternary systems (amino acid + urea + water): L- lysine monohydro chloride/ Larginine / L-histidine + 0.5 M aqueous urea solutions and (saccharides + amino acid + water) : D - glucose/ sucrose / Maltose + 0.5M aqueous L- lysine monohydro chloride / Larginine solutions as a functions of concentration at different temperatures: 298.15, 303.15, 308.15, 318.15 and 323.15 K. The measured density values exhibit usual increasing trend of variation with an increase in amino acid / saccharide concentration and a decreasing trend with an increase in temperature for the systems under investigation. The ultrasonic velocity values have been found to be increasing with an increase in concentration and temperatures in all the systems studied. The increase in ultrasound velocity values with an increase in amino acids concentration has been attributed to an over all increase in cohesion in solution brought above the solute-solute and solutesolvent interaction. Using ultrasonic velocity and density data, the parameters such as isentropic compressibility (Ks), change (and#61508;Ks) and relative changes (and#61508;Ks / Ko) in isentropic compressibility, newlinespecific acoustic impedance (Z) and relative association (RA) have been computed. These parameters provide a basis for understanding the type and the extent of inter molecular interactions, such as weak a strong or no interaction at all. The decrease in compressibility with increase in the thermal breaking of solvent components, which results in greater attractive forces among the molecules of a solution. Decrease in the Ks values with increase in composition is due to greater attractive forces among the molecules of a liquid. Specific acoustic impedance values exhibit increasing trend of variation with an increase in amino acid / saccharide concentration and temperature.The apparent molal volumes (and#61542;v) and apparent molal isentropic compressibility (and#61542;k,s) have been calculated as functions of concentration