Killing Taq

Warren Gallin wgallin at
Mon Oct 2 19:44:22 EST 1995

In Article <44pfm3$fv at>, HAVILAND at KIDS.WUSTL.EDU
(David L. Haviland, Ph.D.) wrote:
>In <DFKoHC.851 at> horton at writes:
>> jim hartley (jhartley at wrote:
>> : Has anyone tried inactivating Taq polymerase (so restriction enzyme ends 
>> : are not blunted) by zapping the dNTPs with alkaline phosphatase? Protocol 
>> : would be easy: add CIAP, incubate, kill with 94 C incubation, then 
>> : ethanol precipitate and cut with RE.  Seems like it should work.
>> You CAN kill Taq with heat, too; how 'bout a 99 C incubation for 20 min?
>A long incubation >95'C *should* do the trick.  But that would depend on 
>the particular enzyme.  If I recall, Hot-Tub had a longer life at >95'C 
>than did native Taq - but then it has been about 4 years since I've seen 
>the activity profiles.  However, in his making and purifying KlenTaq, Wayne
>Barnes described his findings in his Gene 112:29-35 (1992) paper.  It is
>buried in the fine print of the Mat & Methods.  There, he found that Taq
>survived phenol, chloroform, and EtOh precipitation by demonstrating
>32P-dNTP end filling activity by Taq.  The only way he found to completely
>inactivate Taq (KlenTaq) was by a PEG precipitation of the final PCR

In addition, after 20' at 99 deg C, your DNA will all be single stranded,
and you will have to be reasonably careful in trying to anneal it back to
double stranded.  I think PrK digestion is a better solution, both in theory
and in practice.

Warren Gallin,
Department of Biological Sciences, University of Alberta
wgallin at

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