PEG

Michael Witty mw132 at mole.bio.cam.ac.uk
Thu Nov 30 08:33:31 EST 2000


Dear Emir, I am using the same apparatus, solutions (and new solutions)
and types of samples as previously used with success.  Actually the
problem has dissappeared BUT I do strongly suspect our water supply.
Whenever a water purification cartridge is replace this problem appears.

My interest remains because I want to know how PEG could act to make PAGE
go bad.  Regards, Mike.

On Wed, 29 Nov 2000, Emir wrote:

> Michael,
> I believe you are not overloading your gels with protein, as well as you are
> not using old precast or hand-made gels that may have gaps between the gel
> and the glass walls, as well as you are using a good staining solution that
> still have a fixing agent (acid), do you?
> Emir
> >
> > An effect of polyethylene glycol 8000 on protein mobility in sodium
> > dodecyl sulfate polyacrylamide gel electrophoresis and a method for
> > eliminating this effect.  Odom,O.W., Kudlicki,W., Kramer,G., Hardesty,B.
> > Analytical Biochemistry 245:249-252
> >
> > p249 "The mobilities of the three largest proteins (in the standard
> > proteins used) increase with PEG, while those of the two smallest proteins
> > decrease"
> > p249 "It is seen that those proteins behind the PEG move front move
> > faster than normal, while those ahead of the PEG move more slowly".
> >
> > Which is similar to what I see, but I get much more smearing.
> >
> > p250 "Kurfurst reported that the PEG migrates during PAGE only in the
> > presense of SDS this is undoubtedly due to the fact that PEG binds to
> > the SDS micelle".
> >
> > AHA
> >
> > (though PEG can also cause anomolies in DNA gels which contain no SDS!)
> >
> > p250 the authors reduced the formation of PEG/SDS micelles and
> > the bad PEG effect by reducing the concentration of SDS from 0.1 to 0.05%
> > and tris from 125 t 93.8mM.
> >
> > p250.-1.4 "It is still unclear exactly how the PEG-micelle complex affects
> > protein mobility...".
> >
> > Any ideas out there?  Mike.
> >
> 
> 
> 
> 






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