Density, Viscosity and Dielectric Constant of Aqueous Solutions of Triglycine and Tetraglycine

The density, viscosity, static dielectric constant and microwave dielectric loss of aqueous solutions of triglycine and tetraglycine have been studied at various temperatures from 0 to 60 °C. A very similar electrostrictive effect is observed for triglycine and tetraglycine solutions, indicating a different conformational behaviour of the two peptides in solution. The density b-coefficients decrease with temperature and suggest solute-solvent interactions which are also supported by the viscosimetric results. The viscosity 5-coefficients are always positive and the sign of dB/dT indicates that the two peptides are structure-breaking molecules. The dielectric data show the existence of extended hydration sheaths with a different thermal stability for the two peptide molecules. The dielectric relaxation times and the activation enthalpies for these processes are estimated.