Transformation of E. coli

  1. Thaw competent cells carefully on ice
  2. Incubate the DNA with the competent cells for 1-10 min on ice
  3. Incubate for 30-90 sec. at 42°C (heat shock)
  4. Spread the cells on the plates with the appropriate selection marker
  5. Incubate plates over night at 37°C

This procedure works excellent with ampicillin as a selection marker.
With kanamycin or streptomycin transformation rates are ten times lower.
With chloramphenicol as a selection marker this method failed in our hands

For more information see: Brian Pope and Helen M. Kent
High efficiency 5 min transformation of Escherichia coli
Nucleic Acids Research 1996, Vol. 24, No. 3, 536-537