Mg and PCR

Petur Henry Petersen php at
Sun Jan 16 13:01:45 EST 1994

In <2gvss7$9gv at> annag at (Anna Georgalis) writes:

>Can anyone explain or give me a reference on why magnesium produces extra bands 
>when it is in excess in the PCR reaction? One suggestion has been that primers bind non-specifically to other DNA regions and so produce extra bands in the PCR reaction.
>Why should this happen whem Mg is in excess?                                                   

>Thanks in advance.

>Anna Georgalis
>Victorian Institute of Forensic Pathology,

	Well, according to the chapther on Taq DNA polymerase in PCR
techhnology ( Henry A. Erlich Stocton Press 1989) page 18:

	" Taq polymerase activity is sensitive to the concentration of
Mg "

	~ High is inhibitory but it needs some ( I think ) to function.

	ala I think it is the polymerse but it could be the primers too.
One could imagine that excess Mg++ would stabilise the primers and therefor
they would not have as much affinity for the "right place".


	php at

	....No we dont kill whales anymore! Happy?

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