Genetically engineered charge modifications to enhance protein separation in aqueous two-phase systems: Charge directed partitioning
- Iowa State Univ., Ames, IA (United States). Dept. of Chemical Engineering
This report continues the authors` examination of the effect of genetically engineered charge modifications on the partitioning behavior of proteins in aqueous two-phase extraction. The genetic modifications consisted of the fusion of charged peptide tails to {beta}-galactosidase and charge-change point mutations to T4 lysozyme. In this study, they examined charge directed partitioning behavior in PEG/dextran systems containing small amounts of the charged polymers diethylaminoethyl-dextran (DEAE-dextran) or dextran sulfate. The best results were obtained when attractive forces between the protein and polymer were present. Nearly 100% of the {beta}-galactosidase, which carries a net negative charge, partitioned to the DEAE-dextran-rich phase regardless of whether the phase was dextran or PEG. In these cases, cloudiness of the protein-rich phases suggest that strong charge interactions resulted in protein/polymer aggregation, which may have contribution to the extreme partitioning. Unlike the potential-driven partitioning reported previously, consistent partitioning trends were observed as a result of the fusion tails, with observed shifts in partition coefficient (K{sub p}) of up to 37-fold. However, these changes could not be solely attributed to charge-based interactions.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 37346
- Journal Information:
- Biotechnology and Bioengineering, Vol. 46, Issue 1; Other Information: PBD: 5 Apr 1995
- Country of Publication:
- United States
- Language:
- English
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