Application of aqueous mixtures of polypropylene glycol or polyethylene glycol with salts in proteomic analysis

Partitioning of Bovine serum albumin (BSA), β-lactoglobulin (β-LG) and zein as model proteins in aqueous two-phase systems (S) containing polypropylene glycol (PPG425) or polyethylene glycol (PEG 6000) and salts (MgSO₄, (NH₄)₂SO₄, Na₂SO₄) is presented in this paper. The effects of different factors such as tie-line length, salt type and polymer type on the partition coefficient and recovery percent of proteins were analysed. The model proteins were separated by these systems (S) and directly used for gel electrophoresis without separating the target proteins from phase-forming reagents. The results revealed that the S, studied in this work could be used as a novel prefractionation method in proteomic analysis and could separate proteomic proteins in multigroup by one step extraction.