Wizard Mini-preps

Rick Wilson rick at TAQ.WUSTL.EDU
Tue Feb 15 16:02:26 EST 1994

In article <2jdq7m$3t3 at news.bu.edu>, pfoster at bu.edu (Patricia Foster) writes:
> Dear Netters,
>    I have been checking old and new labels from
> Magic/Wizzard kits.  It seems that the significant
> change was from guanidine thiocyanate (old) to
> guanidine HCl (new)...

Actually, there's more to it than that.  A friend who used to work at
Bio-Rad told me that the old kits used diatomaceous earth as the resin.
However, a little saber-rattling from Bio-Rad, who holds the patent on
diatomaceous earth for DNA purification, convinced Promega to change the
resin in their kits.  The new kits contain glass fines as the resin; same
stuff as in the Geneclean kits.  Diatomaceous earth has a much higher
binding capacity for double-stranded DNA, thus your yield problems.

Incidentally, you can buy both diatomaceous earth and glass fines in bulk
for next to nothing, there are lots of protocols floating around for
preparing and using them, and they work great!


Richard K. Wilson, Ph.D.
Genome Sequencing Center
Washington University School of Medicine
St. Louis, MO   63108   USA
(314) 286-1804   rick at geneman.wustl.edu

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