Restriction enzymes @ -20

D.K. dk at
Fri Sep 28 19:05:23 EST 2001

Jill Johnston <johnstoj at> wrote:
>Since most restriction enzymes are labile in aqueous solutions, 

That is, generally speaking, not true. In fact, compared to many
other enzymes, most REs are very robust proteins. But almost 
every protein is labile at very low concentrations.

>I have
>assumed for a long time that they could be inactivated by freezing the
>digest. It seems to be true but I have been asked to confirm by
>hypothesis.  Does anyone have any comments,suggestions

You can kill almost every protein by repeatedly freezing it slowly,
so again REs are not exception here. It is a safe bet that such freezing 
would only kill 50-90% of activity, however. Thus, if you need to
inactivate the enzyme, you still should use heat.


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