Concentration of dilute proteins for SDS-PAGE

[Stephen R. Decker]

Joe Stains <JPS144 at psuvm.psu.edu> 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 Stains


Joe,

If you only have a single protein and know it's properties, why not bind it onto a 
small (<= 1.0 mL) chromatography column and elute with a small volume of buffer.  
BioRad makes a variety of 1 mL disposable pre-packed columns (econo-pac) or you could 
use a self-pack column.  You might even try using free column packing and mixing with 
your sample under binding conditions and spinning it down. Pour off the SN and mix 
with a small volume of elution buffer.  Spin down and save SN.

I have used the column method to concentrate protein from >100 mL down to 1-2 mL.  It 
is quick and easy and there are no harsh chemical treatments or precipitations to 
mess up the protein.  The disadvantage is that it will only work if all of the 
proteins of interest will bind to the same column material and elute from same.

good luck

Steve Decker