"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 0.15 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: In K-i = a(io) In K-o + b(io) where K-i and K-o are the distribution coefficients for any protein in the ith and oth two-phase systems. Coefficients a(io) and b(io) are constants, the values of which depend upon the particular compositions of the two-phase systems under comparison. (C) 2008 Published by Elsevier B.V.

keywords

SOLVATION ENERGY RELATIONSHIP; BIPHASIC SYSTEMS; POLYETHYLENE-GLYCOL; ORGANIC-MOLECULES; METHYLENE GROUP; HYDROPHOBICITY; ACID; CHARACTER; PHASES; SALT

subject category

Biochemistry & Molecular Biology; Chemistry

authors

Madeira, PP; Teixeira, JA; Macedo, EA; Mikheeva, LM; Zaslavsky, BY

our authors

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