Ammonium Sulfate

Dr. Artem Evdokimov eudokima at
Tue Aug 7 18:42:53 EST 2001

And if you intend to crystallize the protein, don't do this. Even
ammonium sulphate precipitation may not be safe, in fact.


Dima Klenchin wrote:
> "Marie France  Janelle" <mariefrancejanelle at> wrote:
> >I used ammonium sulfate to precipite a little protein (12 kDa). I want to
> >get rid of ammonium sulfate now. Is someone have a method to do that
> >successfully?
> To the already mentioned in other replies I can add this:
> Usially 12K proteins are quite simple and withstand quite harch
> treatments. If yours is such a case, an attractive possibility can be
> organic solvent precipitation. Say, you have your pellet after AmSO4
> cut, you resuspend it in water/buffer, then add enough acetone
> (isopropanol, dioxane or whatever works best keeping protein alive),
> your protein precipitates and you resuspend it in whatever you like.
> The advantage to dialysis is speed (fast) and keeping concentration
> high. Works only for select proteins, _usually_ small.
>         - Dima

|Dr. Artem Evdokimov   Protein Engineering |
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