Freezing PCR products

Jim Owens jow at helix.nih.gov
Fri Mar 18 08:58:16 EST 1994


In article <CMu1An.n2w at ncifcrf.gov> Paul N Hengen,
pnh at fcsparc6.ncifcrf.gov writes:
>Interesting enzyme story. Did he ever try to store the enzymes using
these
>different methods, or just feel confident about what he was doing? :-)

No, he had never stored his enzymes any other way.  Always as ~25ul drops
in vials with holes, submerged in liquid nitrogen.  He just found the
article as a justification for what he always had done.

As an additional remark:  He found that a very old enzyme prep, which he
used as a reference for subsequent changes in prep protocols, had
retained its specific activity (units/mg protein determined by Lowry
assay) but had slowly increased in units/ml!  The best guess for the
explanation is that ice was either slowly dissolving in the liquid
nitrogen or was subliming off without loss of enzyme.

Another historical (hysterical?) vignette from

Jim Owens



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