Q: Properties of Phospho-cellulose (P11, Whatman)

[Randall Willis]

Dima,

Unfortunately, what Whatman says is true.  I have worked with P11 off 
and on for over 8 years and have found it to be the most intractable 
resin on the market.  With no shelf life and very labile active groups, 
the reproduceability of the resin from preparation to preparation is 
aggravating.

My recommendation would be to find another resin.  If you need a cation 
exchanger, try CM cellulose (weak) or sulphopropyl (SP, strong) instead.  
I believe that Whatman sells both and I know that Pharmacia sells the SP 
in a variety of resin bead types.  If the phosphate is key to your 
binding, may I recommend that you generate your own resin.  In our case, 
we have affixed phosphotyrosine to CNBr-activate sepharose 4B 
(Pharmacia) and use this to purify P-Tyr binding proteins.

It's a drag and I would love it if someone could produce a good 
phosphorylated resin but nothing is out there of which I am aware.

Good luck...Randall C Willis           Publisher
            Biochemistry Research      Aliquotes Press
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            willis at gandalf.psf.           
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