Separation process using ligand-modified aqueous two-phase system based onstress responsive behaviors of proteins

The possibility of a heat stress-mediated bioseparation process, which util izes aqueous two-phase systems modified with functional ligands such as Tri ton X-405 and Cb-PEG, has been investigated. The change of the surface prop erties of several proteins caused by their conformational change has been q uantified under heat stress conditions. Based on these results, a novel pro tein separation process has been presented using aqueous two-phase partitio ning systems under heat stress conditions. It was found that the partition coefficient of the target protein could be controlled by the combined use o f (i) its stress-responsive behavior and (ii) spontaneous binding with the functional ligands under optimal stress conditions. As a case study, a targ et protein, alcohol dehydrogenase, has been successfully separated from oth er proteins by using ligand-modified aqueous two-phase systems at a specifi c temperature of 50 degrees C.