LIQUID-LIQUID-EXTRACTION OF A RECOMBINANT PROTEIN, CYTOCHROME B(5), FROM AN IMPURE EXTRACT USING AQUEOUS 2-PHASE SYSTEMS

The recovery and purification of a recombinant protein, cytochrome b(5 ), from an impure extract of Escherichia coli disrupted cells was carr ied out in one step using a liquid-liquid extraction process of aqueou s two-phase systems of polyethylene glycol (PEG) and potassium phospha te salts. With this separation process it was possible in one single s tep to remove the cell debris, that precipitate at interface of the sy stem, and to obtain relatively high recovery yields, nearly 67%, of th e target protein in the salt-rich phase, with purification factors up to 6.