Dear Vernon:
The three methods are wonderful for dialysis-based concentration. The
last of them (inserting the dialysis tube into dry Sephadex) has
something in common with a method of chromatographic concentration:
instead of just trapping the H2O with dry Sephadex until you get the
desired final volume of concentrated protein, you can pack a column with
some dry Sephadex, load your sample on top, and continue adding the
desired final volume dH2O or another buffer on top, until you collect at
the bottom. (This could also be done in a spun column.) This
procedure, in addition to the advantages of incredible speed and
possibility to be performed at 4 deg Celsius, will also desalt or allow
buffer exchange, depending on what you add on top until you collect the
first fractions.
This can work quite well for some viruses that cannot be easily
concentrated otherwise.
Best regards,
victor
RE>concentrating protein
7/26/2000
Jennifer-
A couple of years ago, there was a discussion about how to concentrate
protein samples by dialysis, without introducing carbohydrate that would
mess up AAA. Below are some excerpts from those exchanges. The methods
might have some advantages, in that there's less agitation and lower
surface area contact.
Vernon
Vernon A. Shoup
Regeneron Pharmaceuticals
vernon.shoup@regpha.com
--------------------------------------------------
11/6/98
Angela [Murphy] and Vernon,
I've used an even lower-tech method for concentration - hang your
dialysis
bag in an air stream (the inlet of a fume hood is good for this) and
just
watch the volume drop as the water evaporates through the tubing!
Cheers,
Roger [Murphy]
At 09:07 AM 05-11-98 -0400, you wrote:
> FWD>Hydrolysis protocols; low-tech concentrating_ 11/4/98
15:16
>
>
>Angela-
>
>Many years ago, I was able to very effectively concentrate a protein by
>dialysis against a 10% solution of high molecular weight polyethylene
>glycol. Unlike sucrose, the PEG was just too big to diffuse through
the
>pores of the membrane. [Maybe one should add some buffer to the PEG
solution.]
>Another low-tech method of concentrating a protein is to pack the
dialysis
>tube (containing the protein solution) in dry sephadex. The sephadex
will
>"trap" the water diffusing through the membrane pores, thereby
concentrating
>the protein.
>
>Vernon
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