Structure Making / Breaking Tendencies of Various Amino Acids & Peptide: Apparent & Partial Molar Volumes, Partial Molar Expansibilities, Hepler Equation, Interaction Coefficients Etc.

These data have been used to arrive at the various parameters like partial molar volumes and their corresponding transfer functions, side chain contributions, interaction coefficients, activation parameters and hydration numbers. These parameters have been used to rationalize the nature of interactions amongst various amino acids/diglycine (solutes) and water (solvent) in the presence of various electrolytes. From the comparison of partial molar volumes of studied amino acids in aqueous solutions of sodium nitrate[Soto et al. (1999)], NaCl[Bhat et al. (1985)], sodium sulphate[Wadi and Ramasami (1997)] and sodium acetate[Banipal et al. (2004)], it may be observed that apparent molar volumes may vary with the change in concentration of electrolytes. As the anionic part of the salts is mainly modulating the behavior of partial molar volumes because the cationic part is same in the above salts. However in case of L-valine and L-leucine with the increase in the size of nonpolar side chain, the hydrophobic effect also starts influencing the partial molar volumes. Thus there is a competition between interactions due to the anionic part of salts and hydrophobicity of the various amino acids.