Qiagen Maxiprep Problem
benny at holmes.cancres.nottingham.ac.uk
Tue Apr 4 18:12:20 EST 2000
I have been using Qiagen Maxiprep to prepare plasmids for transfection and
the yield hasn't been too satisfactory. Recently, I found that when I let
the drop of ethanol that sticks on the side of tube evaporate off after IPA
precipitation and EtOH wash, a while precipitate forms where that droplet
sticks. This has led me to think that maybe the DNA has not been
sufficiently precipitated out of the solution. Is that a possibility?
I used 150mL of E coli culture and get only about 100 micrograms of plasmid
out. Given my experience described above, is there any way I can improve the
I also notice some white precipitate that has probably co-precipitated with
the DNA but will not redissolve on the addition of Tris, even after warming
to 37 degrees for a period of time. Very often I just have to spin it down
and take the supernatant as the DNA. Does anyone else experience this also?
Any advice will be appreciated. Many thanks.
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