Concentration of dilute proteins for SDS-PAGE

[Kimberley Hobbs]

On Fri, 3 May 1996, Lyle Najita wrote:

> 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
> 
> 
 You could also try concentrating with a gradient mixer. If you hook it 
up to a nitrogen tank it works well. I have used it to concentrate plasma 
for application to columns.