On 15 Oct 1996, Michael Sachsamanoglou wrote:
> What happens when a restriction endonuclease solution is frozen to -80C?
It gets solid.
> Is it normal for the 50% glycerol storage solution to solidify at this
Sure it is.
> I've heard sometime ago that if a restriction enzyme
> freezes it is dead. Is this true?
No. When it is shipped in dry ice, it is normally frozen, is it not? But
if you find it frozen at -20, normally beacuse some ice from the bucket got
in to the tube, it may be dead.
I have heard that many frozen/defrozen cycles are bad, but I never tested
it. Lower temperatures will be better for conservation, but I think we keep
it at -20 because the convienence of the liquid phase.