If running a SDS page is the only motive you can try ppting using TCA.
Bring the final volume of sample to 5% TCA (10% if very dilute-- use 10% to
be on the safe side). Keep on ice for 5-10 min and spin in
cold--microfuge, table top, anything depending upon your volume).
Wash ppt with ethanol (1/4 to 1/2 your total volume of sample)--this
removes any residual TCA
Dissolve ppt in loading buffer.
Sometimes you still have some TCA left which decolorises the bromophenol
Just add a microliter of .01N NaOH or 100mM Tris.... anything to raise the
It worked for me........You may give it a shot too
It also helped me to desalt samples before running.
Katherine Walstrom wrote:
> I have some dilute protein samples that I need to concentrate and run on
> an SDS-PAGE gel. I can't find a detailed protocol for precipitating
> proteins, although what I've read suggests that ethanol works well. I
> want to precipitate all the proteins, not just selectively precipitate
> some of them. Does anyone have a general protocol for this?
>> Thanks much.
>> Katherine M. Walstrom, PhD
> Division of Natural Sciences
> New College of USF
> 5700 N. Tamiami Trail
> Sarasota, FL 34243
>kwalstro at sar.usf.edu