Frost-Free

[Steven_H Harwood]

On 21 Dec 1994, Bruce Phillips wrote:

> 
> 	I have kept restriction endonucleases, quite a few in fact, in a
> -20C frost-free freezer and they retained good activity for up to 6 years.
> Included were SstI, KpnI, EcoR1, XbaI, etc.  The tubes were sealed well.
> The high glycerol (and other?) cryoprotective reagents seem to work very
> well for these reagents.
> 
While polymerases, ligases, etc. are very sensitive to temperature, frost 
free freezers "thaw" only very briefly.  I would think that any 
reasonable container such as styrofoam boxes or even eppendorf 
tube 
holders would offer enough protection from the periodic and momentary 
temperature fluctuations in FF freezers to protect temperature labile 
enzymes from loss of activity. > 

-Steve Harwood
Dept. Ag. Chem.
Oregon State University
Corvallis, OR  97331