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  • 1 Xi’an Polytechnic University College of Environment & Chemical Engineering Xi’an 710048 China
  • | 2 Northwest University Institute of Modern Separation Science Xi’an 710069 China
  • | 3 Peaking University Institute of Physical Chemistry Beijing 100871 China
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Abstract  

Calorimetric measurement of adsorption enthalpies of native lysozyme(Lyz) on a moderately hydrophobic surface at 25°C, pH 7.0 and various salt concentrations was performed. Based on the thermodynamics of stoichiometric displacement theory (SDT), we calculated the fractions of thermodynamic functions involving four subprocesses during a displacement adsorption process from the directly determined enthalpies in combination with adsorption isotherm measurements. The thermodynamic fractions reveal the relative degree of the four subprocesses for contributions to enthalpy, entropy and free energy. The results show that native Lyz adsorption on a moderately hydrophobic surface is an entropy driven process contributed mainly by conformational loss of adsorbed Lyz.