Journal of Thermal Analysis and Calorimetry

, Volume 83, Issue 3, pp 587–595

Thermochemical, volumetric and spectroscopic properties of lysozyme–poly(ethylene) glycol system

  • Zielenkiewicz W 
  • Swierzewski R 
  • Attanasio F 
  • Rialdi G 
Article

DOI: 10.1007/s10973-005-7417-x

Cite this article as:
Zielenkiewicz, W., Swierzewski, R., Attanasio, F. et al. J Therm Anal Calorim (2006) 83: 587. doi:10.1007/s10973-005-7417-x

Abstract

Investigations of lysozyme–polyethylene glycol system were made by differential scanning calorimetry, fluorescence and density techniques. The values of unfolding enthalpies, ΔHNU, unfolding temperatures, Tm, excess molar heat capacities, ΔCp, and apparent molar volumes, VΦ , were determined as functions of PEG concentration. The three PEGs of average molecular mass (MW) 6000, 10000, 20000 were used as macromolecular crowding agents. The concentration of polymers was changed in the range 0–30% mass per volume (w/v). The values of ΔHNU remained constant with no dependence on PEG concentration, while PEG addition to buffered lysozyme solutions caused linear decrease of Tm. The values of ΔCp and VΦ of lysozyme dramatically changed in the range of 8–10% of PEG concentration. The fluorescence spectroscopy was used in order to investigate the polymer influence on possible solvent–lysozyme interactions. The electrical properties of polymer–water and polymer–buffer systems, the dielectric constants of solutions were determined with use of impedance spectroscopy.

Keywords

density DSC fluorescence intensity lysozyme unfolding macromolecular crowding PEG preferential hydration 

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Zielenkiewicz W 
    • 1
  • Swierzewski R 
    • 1
  • Attanasio F 
    • 2
  • Rialdi G 
    • 2
  1. 1.Institute of Physical Chemistry of the Polish Academy of SciencesWarsawPoland
  2. 2.Institute for Macromolecular Studies – Division of GenovaCNRGenovaItaly

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