Proteins can be precipitated by TCA, can tripeptides, pentapeptides, hekzapeptides and other oligopeptites can be precipitated by TCA ? What is the amino acid limit ?
It seems that the physical properties, especially the hydrophobicity, of peptides is at least as important as their length with respect to their precipitation by TCA. Please see this article:
https://www.researchgate.net/publication/20555970_Solubility_of_peptides_in_trichloroacetic_acid_TCA_solutions
Also, the recovery of peptides by TCA precipitation may be improved by adding sodium deoxycholate or Sarkosyl as a carrier, as is the case with proteins.
http://lclane.net/text/tca3.html
Article Solubility of peptides in trichloroacetic acid (TCA) solutions
I agree with Adam. The protocol for TCA protein precipitation is as follow,Add 1 volume of TCA stock to 4 volumes of protein sample.
1. Add 1 volume of TCA stock to 4 volumes of protein sample,i.e. in 1.5ml tube with maximum vol., add 250µl TCA to 1.0ml sample.
2. Incubate 10 min at 4°C.
3. Centrifuge in microcentrifuge at 14K rpm, 5 min.
4. Remove supernatant, leaving protein pellet intact.
5. Wash pellet with 200µl cold acetone.
6. Repeat step 2
7. Repeat steps 4-6 for a total of 2 acetone washes.
8. Dry pellet by placing tubes in 95°C heat block for 5-10 min to drive off acetone.
It is almost 25 minutes procedure, after all cycles we get good yeild.
Dear Yadav, Thank you very much for your response. I could not learn still that are there oligopeptides in supernatant or are they in the pellet ?
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