PEG precipitation
The PEG precipitation is a biochemical method for the precipitation of proteins and plasmid - DNA from a solution with the aid of polyethylene glycol (PEG). Because of its low cost, it is one of the most widely used methods of enriching proteins on a large scale.
principle
Due to its low cost, PEG precipitation is suitable as the first step in the course of protein purification in order to separate proteins and plasmids from other biomolecules . The precipitation takes place via a removal of water and the hydrophobic effect , which is why this precipitation represents the salting out of proteins from a solution, even if PEG is not a salt . PEG concentrations of up to 30% (w / v) of PEG-4000 or PEG-6000 are used. The proteins are not denatured . Without a desalination step, the proteins can be separated from the PEG by ion exchange chromatography . When using PEG-400, dialysis can also be used to remove the PEG.
Alternative precipitations are ammonium sulphate precipitation , TCA precipitation (denaturing), ethanol precipitation (denaturing) and heat precipitation (denaturing). Alternative non-denaturing methods are chromatography- based.
literature
- J. Wen, S. Zhao, D. He, Y. Yang, Y. Li, S. Zhu: Preparation and characterization of egg yolk immunoglobulin Y specific to influenza B virus. In: Antiviral Res . (2012) 93 (1): 154-159, PMID 22127067 .
- Mark Page, Robin Thorpe: Purification of IgG by Precipitation with Polyethylene Glycol (PEG). In: The Protein Protocols Handbook, pp. 1759-1760. 2009, accessed on October 14, 2017 .
Individual evidence
- ↑ KC Ingham: Precipitation of proteins with polyethylene glycol. In: Methods in enzymology. Vol. 182, 1990, pp. 301-306, PMID 2314243 .
- ↑ a b c d e f Alfred Pingoud : Working methods of biochemistry. Walter de Gruyter, 1997, ISBN 978-3-110-16513-5 , p. 56.