title: Partitioning features of bovine trypsin and alpha-chymotrypsin in polyethyleneglycol-sodium citrate aqueous two-phase systems.
abstract: The partitioning of bovine trypsin and alpha-chymotrypsin--proteases of similar physico-chemical properties--in different polyethyleneglycol/sodium citrate aqueous two-phase systems was investigated. The effect of different factors such as polyethyleneglycol molecular weight, pH, tie line length, temperature and the presence of an inorganic salt on the protein partition coefficient were analysed. Both a decrease in PEG molecular weight and an increase in pH led to a higher partition coefficient for both enzymes. Aqueous two-phase systems formed by PEG of molecular weight 3350 and citrate pH 5.2 showed the best separation capability which was enhanced in presence of sodium chloride 3%. The transfer of both proteins to the top phase was associated with negative enthalpic and entropic changes.
authors.affiliation: Chemical Physics Department, Bioseparation Lab., CONICET, and FonCyT, Faculty of Biochemical and Pharmaceutical Sciences, National University of Rosario, S2002LRK Rosario, Argentina.
authors.forename: Gisela
authors.initials: G
authors.lastname: Tubío
authors.forename: Bibiana
authors.initials: B
authors.lastname: Nerli
authors.forename: Guillermo
authors.initials: G
authors.lastname: Picó
mesh_terms: D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000302:isolation & purification*; D002942:Circular Dichroism; D002951:Citrates / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011092:Polyethylene Glycols / Q000737:chemistry*; D000077559:Sodium Citrate; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014357:Trypsin / Q000302:isolation & purification*
chemical_list: D002951:Citrates; D000077559:Sodium Citrate; D011092:Polyethylene Glycols; D002918:Chymotrypsin; C117608:alpha-chymotrypsin; D014357:Trypsin