differentiating between genomic & plasmid DNA

Alexander Kraev kraev at bc.biol.ethz.ch
Fri Feb 21 10:52:27 EST 1997

In article <5ei445$90s at mserv1.dl.ac.uk>, e.hillery at ic.ac.uk (E.Hillery) wrote:

> Would anybody out there have any thoughts on how I could differentiate
> between eukaryotic genomic and pg amounts of plasmid DNA.  In an ideal
> world, I wouls like to separate the two species so that I could then
> quantify the latter
Epicentre Techologies sells the enzyme called ATP-dependent DNAse,
("Plasmid-Safe") which is said to digest any DNA but a supercoiled one.
It is used to clean up preps of cosmids and BAC vectors from the remaining
chromosomal DNA.  It works in my hands, when approx.equal amounts
of supercoiled and linear DNA are  initially present in the reaction.  I
am not sure
though that the enzyme is selective enough to  leave a few plasmid molecules
intact in the presence of a large excess of linear DNA. You could try to set a
mock reaction and find it out...

I hope this helps,

Alexander Kraev, PhD
Biochemie III, ETHZ Zurich
Phone 41-1-632-31-47
Fax 41-1-632-12-13
e-mail kraev at bc.biol.ethz.ch

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