concentrating proteins

[LKM100F at ODUVM.BITNET]

Joe Booth wrote "I've heard that proteins can be concentrated by the addition
of dry Sephadex G-25"  <delete the rest>

  I have used this method, but I don't add the Sephadex directly to my protein
solution.  I put the protein in a dialysis membrane and put the Sephadex on
the outside to suck up the water without risking any protein binding.  It
works OK.  I think PEG (polyethylene glycol) works better; so do Amicon
pressure cells.  Laura Moen  LKM100F at ODUVM.cc.odu.edu  (U.S.)