Author(s):
Madeira, Pedro 
; Teixeira, J. A. ; Macedo, Eugénia ; Mikheeva, Larissa M. ; Zaslavsky, Boris Y.
Date: 2008
Persistent ID: http://hdl.handle.net/1822/10369
Origin: RepositóriUM - Universidade do Minho
Subject(s): Aqueous two-phase systems; Protein partitioning; Collander equation
Description
Distribution coefficients of randomly selected proteins were measured in aqueous two-phase systems (ATPSs) formed by different combinations of Dextran-75 (Dex), Ficoll-70, polyethylene glycol-8000 (PEG), hydroxypropyl starch-100 (PES), and Ucon50HB5100 (Ucon, a random copolymer of ethylene glycol and propylene glycol) at particular polymer concentrations, all containing 0.15 M NaCl in 0.01 M phosphate buffer, pH 7.4. Most of the proteins in the PEG-Ucon system precipitated at the interface. In the other ATPSs, namely, PES-PEG, PES-Ucon, Ficoll-PEG, Ficoll-Ucon, and in Dex-PEG and Dex-Ucon described earlier the distribution coefficients for the proteins were correlated according to the solvent regression equation: ln Ki = aio ln Ko + bio, where Ki and Ko are the distribution coefficients for any protein in the ith and oth two-phase systems. Coefficients aio and bio are constants, the values of which depend upon the particular compositions of the two-phase systems under comparison.
