title: Polyethyleneglycol molecular mass and polydispersivity effect on protein partitioning in aqueous two-phase systems.
abstract: The partitioning of model proteins (bovine serum albumin, ovalbumin, trypsin and lysozyme) was assayed in aqueous two-phase systems formed by a salt (potassium phosphate, sodium sulfate and ammonium sulfate) and a mixture of two polyethyleneglycols of different molecular mass. The ratio between the PEG masses in the mixtures was changed in order to obtain different polymer average molecular mass. The effect of polymer molecular mass and polydispersivity on the protein partition coefficient was studied. The relationship between the logarithm of the protein partition coefficient and the average molecular mass of the phase-forming polymer was found to depend on the polyethyleneglycol molecular mass, the salt type in the bottom phase and the molecular weight of the partitioned protein. The polymer polydispersivity proved to be a very useful tool to increase the separation between two proteins having similar isoelectrical point.
authors.affiliation: Chemical Physical Department, Faculty of Biochemical and Pharmaceutical Sciences, CONICET, FonCyT and CIUNR, National University of Rosario, Suipacha 570, S2002LRK Rosario, Argentina.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Picó
authors.forename: Diana
authors.initials: D
authors.lastname: Romanini
authors.forename: Bibiana
authors.initials: B
authors.lastname: Nerli
authors.forename: Beatriz
authors.initials: B
authors.lastname: Farruggia
mesh_terms: D000465:Algorithms; D000645:Ammonium Sulfate / Q000737:chemistry; D000818:Animals; D002417:Cattle; D005591:Chemical Fractionation / Q000379:methods*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008970:Molecular Weight; D009113:Muramidase / Q000302:isolation & purification; D010047:Ovalbumin / Q000302:isolation & purification; D010710:Phosphates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry; D011506:Proteins / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012710:Serum Albumin, Bovine / Q000302:isolation & purification; D013431:Sulfates / Q000737:chemistry; D014357:Trypsin / Q000302:isolation & purification
chemical_list: D010710:Phosphates; D017680:Potassium Compounds; D011506:Proteins; D013431:Sulfates; C012036:sodium sulfate; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D010047:Ovalbumin; C013216:potassium phosphate; D009113:Muramidase; D014357:Trypsin; D000645:Ammonium Sulfate