TCA precipitation

from Wikipedia, the free encyclopedia
Trichloroacetic acid

The TCA-precipitation is a biochemical method for the precipitation of proteins from a solution with the help of trichloroacetic acid (TCA).

principle

Due to its low cost, TCA 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. The typical mass fraction of TCA in a precipitation is 10% (m / V). This is followed by cooling on ice for half an hour. The proteins are denatured and completely precipitated. After centrifugation , remnants of the TCA can be removed by washing the precipitate several times with ice-cold 80% (V / V) acetone . They can be examined with other denaturing methods, e.g. B. by photometry or by SDS-PAGE . Correct protein folding and thus biological activity is no longer present after the TCA precipitation.

Alternative precipitations are ammonium sulfate precipitation , PEG precipitation , ethanol precipitation (denaturing) and heat precipitation (denaturing). Alternative non-denaturing methods are chromatography- based.

literature

  • AJ Link, J. LaBaer: Trichloroacetic acid (TCA) precipitation of proteins. In: Cold Spring Harbor protocols. Volume 2011, number 8, August 2011, pp. 993-994, doi : 10.1101 / pdb.prot5651 , PMID 21807853 .

Individual evidence

  1. ↑ a b c d e f Alfred Pingoud : Working methods of biochemistry. Walter de Gruyter, 1997, ISBN 978-3-110-16513-5 , p. 53.
  2. ↑ Hubert Rehm : The Experimenter: Protein Biochemistry / Proteomics. Springer-Verlag, 2016, ISBN 978-3-662-48851-5 , p. 22.
  3. ^ L. Koontz: TCA precipitation. In: Methods in enzymology. Volume 541, 2014, pp. 3–10, doi : 10.1016 / B978-0-12-420119-4.00001-X , PMID 24674058 .