Protein Precipitation

u6069416 at u6069416 at
Sat Apr 23 06:13:59 EST 1994

In article <2oejvv$scv at> volcs at (Sam Volchenboum)
>I need to precipitate a protein sample coming off a FPLC column for
>subsequent SDS-PAGE.  I was going to precipitate with 10% TCA and then wash
>with 10% TCA, but I read that the TCA can change the pH so as to affect the
>PAGE.  Then someone told me to wash with acetone.  Fine, but can't I just
>precipitate with one volume of acetone from the start?  Anyways, do any of
>you have ideas/protocols/refs which will precipitate small amounts of
>protein and not affect the PAGE? (Or should I just use TCA and be done with

If the protein sample is in low salt or organic solution (e.g. from reverse
phase chromatogrphy) then I'll just reduce the volume by speed-vac.
If the protein sample is in high salt solution, try ultrafiltration, dilution
with water and ultrafiltration again.
Alternatively, you can try desalting column and change into ammonium
bicarbonate, follow by freeze-dry.
Just some thoughts, hope it helps.


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