SDS-PAGE and guanidine....

Scott Craig s.craig at
Thu Jun 17 19:09:43 EST 1999

This may not be the answer you were looking for but could you use Urea
rather than guanidine in your original sephacryl step. Then the samples
could be run on a SDS-PAGE without the need to remove the urea.
Just a thought

Scott Craig
Dept. of Biotechnology
University of New South Wales
Sydney, Australia

jqpublic at wrote:

> Hello,
> Anyone know a good way to concentrate a protein sample so that it can be
> used is SDS-PAGE if the sample is in 7M guanidine? I have sephacryl
> column fractions in said buffer but need to run 50+ uL in the gel to see
> the bands.
> Using no precipitation causes a 'funky, gunky' ppt to form on top of the
> wells and the electrophoresis does not work. TCA preciptation causes the
> guan. to pp't as well, as does any method requiring a 'cold' step(ice,
> etc).
> I'm currently using a MeOH/chloroform/water method, but it is very
> tedious for 40+ samples and it cannot accomodate volumes of more than
> 150 uL sample to still be done in eppendorf tubes.
> Thanks
> t.a.


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