Conductivity measurements of laccase for various concentrations, pH and ionic liquid solutions

This study investigates the effects of concentrations, pH, the Pyrrolidinium Formate ([pyrr][Fo]) and the Morpholinium Formate ([morph][Fo]) ionic liquids (ILs) on the electrical conductivity of laccase for a wide range of temperatures. We have shown from the effects of concentrations that the higher values of the electrical conductivity are due essentially to cooper ions even the laccase is in its isoelectric point. From Arrhenius law, we have determined the energy of activation to follow the conformational changes. From the variation of the reduced electrical conductivity, we have studied the effects of temperature on the critical concentration c** separating the various concentrations regimes. We have expended by analogy the two-state mechanism model at low and high temperatures to follow the unfolding process and to determine the thermodynamic parameters. The effects of [pyrr][Fo] and [morph][Fo] on the electrical conductivity of laccase are also investigated. We have demonstrated that the electrical conductivity and the energy of activation are intimately related to the ILs characteristics and the laccase conformation.