Combined use of extraction and genetic engineering for protein purification: recovery of beta-galactosidase fused proteins.
Partitioning of beta-galactosidase in aqueous two-phase systems of poly(ethylene glycol) and potassium phosphate is reviewed. The affinity of Escherichia coli beta-galactosidase for the PEG-rich phase dominates also in beta-galactosidase fusion proteins and the concept of using beta-galactosidase as an affinity handle for extraction of other proteins, after fusion, is discussed. A hypothesis is presented, assuming that tryptophan residues at the surface of beta-galactosidase is responsible for its partitioning to the PEG rich phase, and the concept of poly-tryptophan handles fused to the target protein for extraction is introduced.
Department of Biochemistry and Biotechnology, Royal Institute of Technology, Stockholm, Sweden.
S O
SO
Enfors
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K
Köhler
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A
Veide
D005818:Genetic Engineering; D010710:Phosphates; D011092:Polyethylene Glycols; D011188:Potassium; D017680:Potassium Compounds; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification*; D012995:Solubility; D001616:beta-Galactosidase / Q000302:isolation & purification*
D010710:Phosphates; D017680:Potassium Compounds; D011993:Recombinant Fusion Proteins; D011092:Polyethylene Glycols; C013216:potassium phosphate; D001616:beta-Galactosidase; D011188:Potassium