title: Comparison of colorimetric methods for the quantification of model proteins in aqueous two-phase systems.
abstract: In the current study, the quantification of different model proteins in the presence of typical aqueous two-phase system components was investigated by using the Bradford and bicinchoninic acid (BCA) assays. Each phase-forming component above 1 and 5 wt% had considerable effects on the protein quantification in both assays, respectively, resulting in diminished protein recoveries/absorption values by increasing poly(ethylene glycol) (PEG)/salt concentration and PEG molecular weight. Therefore, a convenient dilution of both components (up to 1 and 5 wt%) before protein quantification is recommended in both assays, respectively, where the BCA assay is favored in comparison with the Bradford assay.
authors: Institute of Technical Chemistry, Leibniz University of Hannover, 30167 Hannover, Germany.
authors: Anna
authors: A
authors: Glyk
authors: Institute of Technical Chemistry, Leibniz University of Hannover, 30167 Hannover, Germany.
authors: Sandra L
authors: SL
authors: Heinisch
authors: Institute of Technical Chemistry, Leibniz University of Hannover, 30167 Hannover, Germany.
authors: Thomas
authors: T
authors: Scheper
authors: Institute of Technical Chemistry, Leibniz University of Hannover, 30167 Hannover, Germany. Electronic address: beutel@iftc.uni-hannover.de.
authors: Sascha
authors: S
authors: Beutel
mesh_terms: D002951:Citrates / Q000737:chemistry; D003124:Colorimetry / Q000379:methods*; D010710:Phosphates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D011506:Proteins / Q000032:analysis*; D000077559:Sodium Citrate; D014867:Water / Q000737:chemistry*
chemical_list: D002951:Citrates; D010710:Phosphates; D017680:Potassium Compounds; D011506:Proteins; D014867:Water; D000077559:Sodium Citrate; D011092:Polyethylene Glycols; C013216:potassium phosphate
keywords: Aqueous two-phase system; BCA assay; Bradford assay; Colorimetric analysis; Protein quantification