Concentration of dilute proteins for SDS-PAGE

Giovanni Maga maga at
Mon May 6 11:35:12 EST 1996

In article <96124.144926JPS144 at>, Joe Stains
<JPS144 at> 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

One possible way: dialyze your sample against a buffer with a
concentration of all the components which is, let's say, 10-fold less the
one you have in your starting sample. Then use a speed-vac to concentrate
the sample up to the starting concentration of buffer components (in this
case 10-fold). The dialysis step is in order to avoid to concentrate too
much whatever you have in your buffer, since it could then disturb the run
on the SDS-PAGE. If the kind of buffer does not bother you, just dialyze
against ammonium acetate (at the right pH for your protein) and then
speed-vac it down to the volume you like (in this case you can reduce the
volume to nothing, having only your protein in the lyophilized material at
the end).
It's just an idea...I did it and it worked. Hope the same with you.

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