title: Protein quantification in the presence of poly(ethylene glycol) and dextran using the Bradford method.
abstract: Some experimental methodologies require the quantification of protein in the presence of polymers like poly(ethylene glycol) (PEG) and dextran (DEX). In the aqueous two-phase system (ATPS) extraction of biomolecules, the interference of these phase-forming polymers on the Bradford quantification assay is commonly recognized. However, how these polymers interfere has not been reported hitherto. In this study we show that while dextran concentrations of 20% (w/w) can be used without error, loss of accuracy occurs for solutions with PEG concentrations >10% (w/w). Above this value a substantial decrease on the assay sensitivity is observed.
authors: Center of Chemistry, University of Minho, Braga, Portugal.
authors: Helder
authors: H
authors: Barbosa
authors: Nigel K H
authors: NK
authors: Slater
authors: João C
authors: JC
authors: Marcos
mesh_terms: D002138:Calibration; D003124:Colorimetry / Q000379:methods*; D003911:Dextrans; D007202:Indicators and Reagents; D011092:Polyethylene Glycols; D011506:Proteins / Q000032:analysis*; D012394:Rosaniline Dyes; D012680:Sensitivity and Specificity; D012997:Solvents
chemical_list: D003911:Dextrans; D007202:Indicators and Reagents; D011506:Proteins; D012394:Rosaniline Dyes; D012997:Solvents; D011092:Polyethylene Glycols; C004692:coomassie Brilliant Blue