Source of pure PEG?

Skywalker skywalke at dino.qci.bioch.bcm.tmc.edu
Mon May 17 09:06:10 EST 1993


In article <1993May12.230304.3374 at riscsm.scripps.edu> arvai at riscsm.scripps.edu (Andy Arvai) writes:
 >
 >We have a protein which we are trying to crystallize. There is 5mM
 >magnesium in the protein solution. We have crystallized this in PEG 4k
 >after dialyzing out the magnesium. However it is known that magnesium is
 >required for activity and therefore we would like to crystallize
 >it with magnesium. The problem is that the PEG 4k's we have tried have
 >phosphate in them and this causes magnesium phosphate crystals to
 >form. Phosphate is present because PEG is frequently neutralized by
 >the addition phosphoric acid.
 >
 >Does anybody have a source of phosphate-free PEG or know of a good way
 >to purify the PEG?
 >
 >Andy Arvai 
 >The Scripps Research Institute
 >arvai at scripps.edu 

The best source of PEG we have found it from EM Science, the following 
postscript file is the protocol to purify PEG.


Timothy Reynolds


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