SDS-PAGE and guanidine....

[jqpublic at home.net]

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.