Gert-Jan Euverink gertjan at
Wed Sep 13 05:40:57 EST 1995

In article <sg-1109951635310001 at> sg at writes:
>We wish to purify an enzyme using ion exchange from serum-free conditioned
>medium.  The NaCl concentration is approximately 100 mM.  We would like to
>desalt this medium prior to binding to DEAE-sephadex.  We have tried to
>desalt using buffer exchange (Centri-Prep), however, the enzyme loses its
>activity after desalting by this approach, even if NaCl concentrations are
>raised back to physiological levels!
>Are there any other techniques available that may be used to desalt the
>conditioned medium?

You can try dialysis. If the volume is to large you might consider to 
dilute your sample untill the salt concentration is low enough 
to allow protein binding to DEAE sephadex. Maybe you can do this in 
combination of raising the pH.

Gert-Jan Euverink
gertjan at
The Netherlands.

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