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Chenzhong Kuang

Transformation of plasmid DNA to competent E. Coli cells

Chenzhong Kuang

Ver.1.0 - 7/7/2002

Material and Reagents

  1. SOC

    2% Tryptone
    0.5% Yeast Extract
    10mM NaCl
    10mM MgSO4
    10mM MgCl2

  2. 1.5 mL microfuge tubes

  3. 42°C waterbath

  4. Ice

  5. 37°C shaker


  1. Thaw competent cells on ice. 20-200μL per tube

  2. Add max. 20μL of a ligation reaction

  3. Mix very gently!

  4. Incubate the tubes on ice for 30 min

  5. Heat shock the cells for 45 sec to 2 min at 42°C

  6. Place the tubes immediately on ice for at least 2 min

  7. Add 800μL of SOC medium to each tube

  8. Incubate for 1 hour at 37°C and shake vigorously

  9. Spin down briefly and remove most supernatants

  10. Resuspend cell pellet with the rest SOC medium in the tube by pipetting

  11. Plate out the suspension on a LB agar plate containing the appropriate antibiotic.

  12. Incubate the plates overnight at 37°C



No responsibility is assumed by for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. It is the users responsibility to ensure that all procedures are carried out according to appropriate Health and Safety requirements.