"Re: "Ghost" bands in plasmid preps?"

Mart Speek smart at KBFI.EE
Fri Nov 26 03:34:10 EST 1999

Hi all plasmid miniprep folks:

Yes you're right, the band running just ahead of your cccDNA is
single-stranded form of plasmid DNA. Six-cutter restriction enzymes
dont digest it normally.

To get rid of it, all you need is to reduce the concentration of
NaOH (0.2 -> 0.1 N) in your Sol II. I have tested a series
of NaOH concentrations and found 0.1 N NaOH most
suitable for miniprep purposes (maximum yield + ssDNA minus)

Good luck!


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