CORRELATION OF PROTEIN PARTITIONING IN AQUEOUS POLYMER 2-PHASE SYSTEMS

A correlation is presented for the partitioning of proteins in aqueous two-phase systems. The correlation relates the natural logarithm of the protein partition coefficient to the polyethylene glycol (PEG) concentration difference between the phases, (w1″ - w1′), by the equation, 1n K = A(w1″ - w1′) + b(w1″ - w1′)2. This relationship was shown to fit protein partitioning data obtained from eight two-phase sytems at pH 7.0, four consisting of PEG 8000-Dextran T-500-water systems and four consisting of PEG 3400-potassium phosphate-water systems.Seven different proteins, ribonuclease, lysozyme, trypsin, rhodanese, transferrin, hexokinase and invertase, with a molecular weight range of 10 000-270 000, were utilized in this work. Each of the proteins partitioned with different values of the empirical constants A and b. © 1990.