Storage of purified proteins

Richard_Heath heath at
Wed Dec 14 12:14:09 EST 1994

In article <9412132042.AA12297 at>, geneh at USA.NET (Gene Holowachuk) writes:
> Can anyone suggest some guidelines for the storage of highly purified
> recombinantly produced proteins. We have purified a couple of cytokines
> produced in E. coli, about 1 mg/l. What are the best ways for short term
> and long term storage - 50% glycerol, lyophilized, -70 oC, etc. We have
> found loss of activity when stored at 4 oC for longer than 1 week. Any
> suggestions will be appreciated.
> Cheers :-))
> ===========================================================================
> **  Gene Holowachuk                |  Voice: 607/547-3937                **
> **  Research Institute             |  Fax  : 607/547-3061 (attn Gene H)  **
> **  Mary Imogene Bassett Hospital  |  email: geneh at     **
> **  One Atwell Road                |       : geneh at               **
> **  Cooperstown, NY 13326          |       : geneh at             **
> ===========================================================================
The method you use will probably ultimately depend on the protein you are
storing, and will have to be found by trial and error!  However, when I worked
on an unstable protein, I found that flash freezing in liquid nitrogen was the
only way to go, with storage at -70.  You may want to freeze aliquots, so you
don't subject the protein to repeated freeze/thaw cycles.  Short term, you may
find that -20 is OK - again, avoid too many freeze/thaw cycles.  (Both of these
in regular buffer).  Store small aliquots in different ways, and test for
activity after a week, month etc.

Good luck,

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