transformation efficiency Chung?

Burkhard Hassel b.hassel at
Tue Feb 9 09:44:27 EST 1999

Hi all!

is anybody using the transformation method of Chung et al (PNAS 86,
pp2172-2175) ?
The method is also included as an alternative protocol in Current
Protocolls in Mol. Biol.

The authors claim an transformation efficiency of 1E7 to 1E8 per ug of
DNA (pUC19) but I can reach only 5E5 (with bluescript and DH5 alpha
Can it be that my DMSO is too old? It is stored at roomtemp since one

Apart from the low efficiency, I like the method because it's so pretty
fast and unexpensive.
Hoping for a reply,

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