title: "On the Collander equation": protein partitioning in polymer/polymer aqueous two-phase systems.
abstract: 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 0.15M 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: lnKi=aiolnKo+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.
authors: Laboratory of Separation and Reaction Engineering, Dpt. de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, s/n 4200-465, Porto, Portugal.
authors: Pedro P
authors: PP
authors: Madeira
authors: José A
authors: JA
authors: Teixeira
authors: Eugénia A
authors: EA
authors: Macedo
authors: Larissa M
authors: LM
authors: Mikheeva
authors: Boris Y
authors: BY
authors: Zaslavsky
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D011108:Polymers / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D011108:Polymers; D011506:Proteins; D014867:Water