SDS-PAGE SAMPLES

[Tom Belbin]

In article <32AE143E.3636 at FS1.CE.UMIST.AC.UK>, MJFASKH at FS1.CE.UMIST.AC.UK wrote:

> I'm trying to run protein samples which contain 6 M guanidine HCl on SDS
> PAGE gels, however when I add the sample buffer the sample precipitates
> and if I try to load it on the gel I don't get anything useful back! Can
> anyone suggest a way to get these samples on a gel short of actually
> dialysing them first?
> 
> Alternatively, is there any way of dialysing lots of small samples
> fairly easily without the protein sticking to the membrane?
> 
> Any ideas?
> 
> Karen

Guanidine will ppt in the presence of SDS.  If you do not want to 
dialyze your samples, you might try switching to a buffer containing
8M urea during the procedure (eg. column washing).

Only other thing to do would be to TCA ppt your samples and resuspend them 
in the buffer of your choice.

Hope this helps...

Tom Belbin
Biochemistry Department, Memorial University of Newfoundland
St. John's, NF  Canada  A1B 3X9
Phone: (709)-737-2538   Fax: (709)-737-2422