SDS-PAGE and guanidine....

Dima Klenchin klenchin at
Fri Jun 18 10:12:29 EST 1999

In article <376916DD.462E1B35 at>, lnd at wrote:
:"S. Findley" wrote:
:> Can you exchange the Guanidine for Urea using Those Amicon
:> Microconcentrators? (or something similar)
:> --
:> Seth D. Findley               polliwog at
:> Department of Biochemistry    Phone: 206-543-1710
:> Health Sciences Building J579
:> University of Washington, Box 357350, Seattle, WA 98195
:That's realy good idea and works perfectly. Use green centricone tubes
:(Amicon) and centrifuge your sample with shared new buffer, at 500-100
:rpm (Sorval, HB-4). It takes time, but you can get your sample not only
:washed from Guan..  but also concentrated.  I use this way to
:concentrate protein(s) el.eluted from SDS-PAGE. Sometimes I even use
:those tubes for el.elution, set directly into rod PAGE equipment.

That's really bad idea because it is even more tedious than methanol/
chloroform pption he does not want to use. It is also less quantitative
and MUCH more expensive. I'd say, dilute guanidinium to ~ 1 M and
do TCA. If protein concentration under such dilution becomes too
low for TCA, I'd stick with MeOH/Choroform - it's not really much more
work than TCA. 

        - Dima

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