Is Trifluoroacetic acid toxic for cells? - (Feb/25/2014 )
I am trying to induce beta amyloid aggregation in HEK293 using ab peptide 1-42 (1uM for 7 days, according to "Mechanism of amyloid plaque formation suggests an intracellular basis of Aβ pathogenicity"). Unfortunately, after 4 days all my cells died. We took a look at ab salt composition and realized that 26% is composed by TFA. I would like to know if this salt is toxic for cells or the massive death has another reason.
Thank you in advance!!
I'd hazard a yes, it will be toxic - it is used to precipitate proteins in purification. Check the MSDS for toxicity levels in animals. However, the toxicity always depends on dose, how much are you adding to your cells?
You may be able to dissolve the Ab-peptide and then dialyse to remove the salt.
I'm using 0,7 microM of TFA. Unfortunately, Sigma doesn't give any information about toxicity levels . By the way, I phoned them today and they didn't have an answer for my question " Is the ab peptide 1-42 suitable for cell culture?" - "Well, we don't know. You have to test". Dear Lord.
Thanks, Bob! I will try to dialyse the peptide or maybe find another without TFA as a salt.
I was wondering if 100% HFIP or 1% NH4OH are able to "neutralize" (or something like this), the TFA. Sorry for this silly question!
Because according to the manufacturers, the ab should be initially dissolved in 100% HFIP or 1% NH4OH, sonicated, dried and re-suspended in 100% DMSO or 10X PBS. We don't have a drier machine in our lab, so we diluted the peptide in 60mM NaOH, sonicated and added PBS to our final concentration.
No idea sorry. NH4OH should neutralize, but then, so should any other base. HFIP seems to be a strongly polar solvent useful for dissolving hydrogen bond acceptors. I suspect that you won't be able to fully re-dissolve the peptide in NaOH as the presence of the TFA will prevent it from dissolving properly, but I can't see why this wouldn't work when NH4OH does.
LFS on Tue Feb 25 21:55:12 2014 said:
By the way, I phoned them today and they didn't have an answer for my question " Is the ab peptide 1-42 suitable for cell culture?" - "Well, we don't know. You have to test". Dear Lord.
ab 1-42 may be too "sticky" for cell culture, maybe 1-40 will be better.