Phil Harrison wrote:
> Now for the question (you probably thought I'd never get there!) Any
> suggestions on how to freeze-dry this sample and get a powder instead of goo?
Is freeze-drying realy required? Can you store the protein frozen in
small aliquots? Or in 50% glycerol at -20?
Many proteins store well as an ammonium sulfate precitate at 4 degrees.
Also, if you have used aceton-powders in the past, can you precipitate
the purified protein once from a fairly concentrated solution (say,
10-100 mg/ml)? That way you would use only a little aceton, which can be
disposed of in the sink (wash with plenty of water).
If you need to lyophilise, make sure you do it from a suitable buffer. I
once had to lyophilize from an ammonium formiate buffer. The idea was
that both ammonia and formic acid are volatile, and I should have been
left with the pure substance. In practice, the ammonia and the water
went of and I ended with my substance in concentrated formic acid, which
did not improve its quality ;-(
