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Pfu polymerase in PCR

Dr. Duncan Clark duncan at genesys.demon.co.uk
Tue Feb 11 04:38:16 EST 1997

In article <fof1-1002971723410001 at saentis.biologie.uni-konstanz.de>,
"Frank O. Fackelmayer" <fof1 at chclu.chemie.uni-konstanz.de> writes
>Pfu is a proofreading POLYMERASE. It will NOT degrade your DNA in presence
>of nucleotide triphosphates (this is why you should add the polymerase
>last). Only after misincorporation of a nucleotide, Pfu will remove this
>nucleotide and then continue polymerizing. 

Not quite true. Unannealed primers are single stranded and even in the
presence of dNTP's the 3-5 exonuclease will attack them. When they are
annealed as a duplex in the prsence of dNTPs polymerisation occurs and
the exonuclease is inhibited from action but only on the duplex.

The problem with being on the cutting edge is that you occasionally get 
sliced from time to time....

Dr. Duncan Clark
DNAmp Ltd.
TEl/FAX 01252376288

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