Ammonium Sulfate

Dima Klenchin klenchin at
Tue Aug 7 18:36:15 EST 2001

"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

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

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