Storage of purified proteins

Giovanni Maga maga at
Thu Dec 22 07:01:34 EST 1994

In article <3d4bea$rrg at>, Hiesberger Thomas
<hiesi at> wrote:

> In article <66445.ashendel at> Curt Ashendel,
> ashendel at 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.
> Hi 
> If you still have problems to store your protein after all this good
> ideas, try to get your protein to the highest concentration you can. If
> this is not possible, you should try to store it in a puffer containing a
> other protein in high concentration. (Add BSA to 20mg/ml). Proteins do
> like proteins. But this is only possible if you chose a protein which
> does not interfere with your experiments. 
> Thomas

A small addition:
If it's not too trivial, why do not try also in liquid nitrogen?
Flash-freezing in the presence of glycerol is a mild treatment which does
not damage too much the protein. One way I found very useful is to make
"pop-corns", just by dropping small aliquots (30-50 µl) of your sample from
a tip directly into nitrogen. Then you can collect these small balls
(pop-corns) in a tube and store them in nitrogen. In this way you don't
need to thaw your whole sample each time and also these pop-corns seem to
survive longer (no loss of activity in 2 years of storage for e.g. DNA
On the other hand, if you already did it, sorry.
All the best,
G.Maga, UNI-Irchel Zurich (CH) Biochemistry
maga at

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