TAQ contaminated with DNA?

Paul N Hengen pnh at fcsparc6.ncifcrf.gov
Mon Aug 29 15:25:33 EST 1994


 In article <Cuzvo3.MyH at ncifcrf.gov>
 pnh at fcsparc6.ncifcrf.gov (Paul N Hengen) writes:

: Don't bet on it.  Even "famous" brands of Taq have DNA contamination
: when you're probing for bacteria at the 50 cell level, and you try and
: boost signal by overdosing on primers (It's NOT primer dimer).  That's
: why Perkin-Elmer has a new Taq which is supposedly DNA-free, which I'm
: going to try today.

| A P-E sales rep told me the older version contains approx. 1 bacterial genome
| per 100 Units of enzyme (not to mention plasmids).

Correction...The original Taq had at least 10 genomes per 2.5 Units, while the
newer "cleaner" version of Taq called AmpliTaq DNA polymerase, LD (for low DNA)
is claimed by PE to have _probably_ no more than 1 genome per 2.5 Units. But,
this is only tested by amplifying with primers to 16S rRNA genes. I don't think
they use primers to known cloning vectors.

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* Paul N. Hengen, Ph.D.                           /--------------------------/*
* National Cancer Institute                       |Internet: pnh at ncifcrf.gov |*
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