Taq polymerase trivia

tom chappell tchappell at znet.com
Wed Nov 24 03:47:05 EST 1999

In article <38387B68.DCED1435 at med.unc.edu>, Stephen Snowdy
<stephen_snowdy at med.unc.edu> wrote:

> Does anyone know why (as if it had a reason) Taq Pol adds an adenine on
> the end of PCR products (as opposed to Pfu which generates blunt-ended
> products).  Got asked this one at a committee meeting and I have no
> idea.

Pfu adds to the ends also, it is just very good at taking it back off
again when it realizes it has made a mistake.

Whether or not you see it on the end of the DNA product is due to relative
rates of pol activity vs. proof-reading activity. 

Pfu-Taq mixes are good for long PCR because when Taq makes a pol mistake,
Pfu can come in and proof it back, allowing for further extension.

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