Prediction of protein partition in polymer/salt aqueous two-phase systems using the modified Wilson model

Abstract

The extension of the modified Wilson model to multicomponent mixtures, presented in a previous publication, is applied to predict the partition of the following proteins: bovine serum albumin (BSA), lysozyme, glucosidase and catalase, in the Na2SO4/PEG6000 and K2HPO4/PEG6000 aqueous two-phase systems at 298.15 K. The results obtained with the model are, in general, in fair agreement with the experimental data. In the modelling methodology adopted here, special emphasis on the so-called charge effects to the protein partition was given. To our knowledge, no experimental information is available in the literature that allows to estimate the interaction parameters between these macromolecules and the components present in the aqueous two-phase systems (water, salts and polymer). Thus, the deviations observed between calculated and experimental protein partition are mainly due to some assumptions made in the predictive methodology.