genomic DNA in plasmid prep

John Dixon jpcd100 at
Thu Jul 23 14:15:26 EST 1998

In article <35B5C3DB.5608 at biodec.wustl.edu_nospammmmmmm>,
graham at biodec.wustl.edu_nospammmmmmm wrote:

> > letting it sit too long in the alkaline lysis buffer


> This may not work on Sundays or Tuesdays or whenever your time is most
> pressed. :) I've yet to find any way of ridding samples of chromosomal
> once its in the prep. (Tried some acid phenol, which can work if the
> plasmid is not also removed.)
> If you can solve this, you will be a hero. (Plese E-mail me if you have
> a clue).

Has anyone tried the PLasmid-safe enzyme from Epicentre I think? I got a
flyer about it once. They have some sort of exonuclease that digests
linear dsDNA and closed circular ssDNA and linear ssDNA, but can't touch
nicked/closed-circular/supercoiled DNA. 

Never tried it myself, but it might do the job you want. Love to hear if
it works.



no affils etc.

John Dixon                                     Lab 44 (1223) 334131
Wellcome/CRC Institute                         Fax 44 (1223) 334134
Department of Genetics
Cambridge University    
United Kingdom                      e-m: jpcd100 at

More information about the Methods mailing list