Concentration from GuHCl ?

newittja at newittja at
Tue Feb 15 20:39:53 EST 1994

Roger Graham <flo at> writes:
>4. from  Michael Morales <mmorales at>
>Although I've never tried it in 6M Guan-HCl, the method of Wessel & Flugge
>(Anal Biochem, vol 138:141-143 (1984)) has worked well for me w/ dilute
>proteins in high salt concentrations. 
I have used Wessel & Flugge's excellent method for concentrating dilute
proteins.  It works with 6 M Guan-HCl, but you have to be careful in the
aspiration steps to remove as much aqueous layer as possible.  I've also
included an extra wash of the pellet at the end of their procedure
with MeOH/CHCl3 (4:1) to help remove excess guanidine, but if you are
careful, this step isn't really needed.  If your protein solution is
concentrated enough, dilute 1:1 with water before ppting with MeOH/CHCl3
and you won't have any problem.  This is an excellent method for working
up samples for SDS-PAGE from solubilized whole cells or fractions.
Unfortunately, DNA ppts as well, so sonication may be required.
	John A. Newitt  <newittja at>

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