PCR buffer with Tris-HCl and Ammonium sulfate (4:1)-does it exist?

Tom Anderson ucgatan at socrates-a.ucl.ac.uk
Thu Feb 5 13:43:18 EST 2004

On 5 Feb 2004, Elisabet W wrote:

> Why is it Ammonium sulfate in my nested PCR mix?

I believe the ammonium is thought to interact with the DNA and somehow
make the reaction less sensitive to annealing temperature, so you get more
product and less nonspecifics.

> Can you by a PCR buffer which contains Ammonium sulfate together with
> Tris-HCL (pH 8.5), when the consentration is 4:1?

If you mean Tris:Ammonium 4:1, then i think Invitrogen do a buffer like
that: their PCR Optimizer kit is based on it. Fermentas do a 10X buffer
with 750 mM Tris and 200 mM ammonium sulphate, if that's any use; they say
they supply it with all their polymerases, so you might even have some
lying around.


Tom Anderson, MRC Laboratory for Molecular Cell Biology, UCL

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