Concentration of dilute proteins for SDS-PAGE

[Lyle Najita]

Joe Stains wrote:
> 
> Does anyone know of any efficient way of concentrating large volumes of
> a dilute protein (several mls) for use with SDS-PAGE?  I have a couple
> of ideas on some techniques, but would be interested in anything anyone
> else may have, as they all have a lot of pros and cons!
> 
> Thanks in advance
> 
> Joe StainsMy personal favorite if you aren't particular about 
recovering active protein after the gel run is to 
precipitate the sample with 0.1x vol. of 100% TCA 
solution.  Mix and let sit for 20 min. to O/N and 
then pellet.  Rinse the pellet with cold acetone to 
remove the residual acid.  You'll know upon 
addition of sample buffer with BPB whether you 
rinsed thoroughly or not.  Be sure not to let the 
pellet get too dry, ie - don't speed-vac the sample 
under heat for long periods of time, you may have 
problems resuspending the pellet.

Lyle Najita
Plant Pathology
University of California - Davis