Urea and ion exchange

Ian Mc i.mcfarlane at icrf.icnet.uk
Wed Jun 30 11:21:22 EST 1999


I'm not sure if I'm remembering this correctly, but don't you have to
deionise urea before use (ie Dowex resin). I'm not sure how urea breaks
down to give charged products tho.

Ian  Mc




In article <57C0B572D021D211834200A0C949D81622156A at MAILSERVER>,
a.krimer at biosidus.com.ar (".Krimer Alejandro") wrote:

>         Dear Netters:
> 
>         I disagree with Roney, may be some protein could bind to ion
> exchange resins; but the general rule is not binding.
>         I have heard some explanations a few years ago about the question. I
> think Urea exposes hydrophobic sites in the protein reducing the interaction
> with a charged matrix.
>         In my experience working with more than 10 different proteins urea
> concentracion should not exceed 2-3 M.
>         Hope this helps.
> 
>         Alejandro Krimer
>         R & D Department
>         Bio Sidus
> 
> > In article <B0001705182 at spider.cigb.edu.cu>, ricardo.silva at cigb.edu.cu
> > wrote:
> > 
> > > Hi all,
> > > Several colleagues of mine have advised me against using high 
> > > concentrations (8 M) of urea in ion exchange runs. In their 
> > > experience, nothing binds under this conditions. This puzzles me, 
> > > because being urea an uncharged species, it shouldn't interfere with 
> > > ion exchange, right?
> > > Does anybody have similar experiences and/or have an explanation?
> > 
> >    All I can say is that I have seen it done a few years ago, and it
> > worked - I believe it was on Q-Sepharose and eluted with KCl. One source
> > of trouble I can think of is to get your eluting salt to dissolve in hi
> > conc urea. Just 2 cents on this one...
> > 
> > roney



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