Protein Precipitation

[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
it...)

Thanks,
Sam