GELSHIFT HELP, No competition

[Stephen R. Lasky]

In article <beavis-0212951411380001 at drwpowermac.med.utah.edu>,
beavis at butthead.utah.edu (beavis) wrote:

> In article <30BD8A2C.58C9 at medkem.umu.se>, Eric Hanson
> <Eric.Hansson at medkem.umu.se> wrote:
> 
> > Thanks,
> > 
> > Eric
> 
> When I've done gel shift experiments with whole yeast cell extracts I will
> first add the "cold" competitor DNA to the reacation containing the yeast
> extract, incubate for 15 minutes--I then add the labeled DNA, incubate for
> an additional 15 minutes and then load the gel.
>  
> jrs

JRS, this is not competition.  You have to add the competitor at the same
time as the labeled ligand (DNA) in order to have a truely competitive
system.   I have no answer to the original question, but if he did the
experiment this way, he would not be looking at competitive inhibition of
DNA binding.

SRL

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Stephen R. Lasky Ph.D.   Brown U/Roger Williams Medical Center,  Providence, RI.   
Phone: 401-456-5672     Fax: 401-456-6569     e:mail: Stephen_Lasky at brown.edu
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