title: Predicting protein partition coefficients in aqueous two phase system.
abstract: The present work aims to achieve an additional insight into the protein partitioning behavior in aqueous two phase systems (ATPSs), together with a study on the viability of a semi-empirical model based on continuum electrostatics to predict the protein partition characteristics. The partitioning behaviors of 14 globular proteins, with different properties, were explored in three polymer/polymer ATPSs. By the Collander equation, a linear correlation between protein partitioning coefficients in all systems was observed. Using the semi-empirical model it was possible to predict the partitioning behavior of proteins. The electrostatic energy depends on the protein size and ATPSs characteristics and varies in agreement with the difference in phase dielectric constants. Linear correlation of nonpolar energy, and the solvent accessible surface area was observed. Polymer structure and concentration have a significant influence on model viability. A good qualitative prediction of preferred phase for studied proteins was observed.
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal; Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal. Electronic address: dragana@tecnico.ulisboa.pt.
authors.forename: Dragana P C
authors.initials: DP
authors.lastname: de Barros
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Sara R R
authors.initials: SR
authors.lastname: Campos
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Azevedo
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: António M
authors.initials: AM
authors.lastname: Baptista
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
authors.forename: M Raquel
authors.initials: MR
authors.lastname: Aires-Barros
mesh_terms: D003911:Dextrans; D005362:Ficoll; D008956:Models, Chemical; D011092:Polyethylene Glycols; D011506:Proteins / Q000737:chemistry*; D012997:Solvents; D055672:Static Electricity; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D003911:Dextrans; D011506:Proteins; D012997:Solvents; D014867:Water; D005362:Ficoll; D011092:Polyethylene Glycols
keywords: Aqueous two-phase system; Collander equation; Partition coefficient prediction; Protein partitioning; Semi-empirical model