Recommended Protocol:

1. Equilibrate a water bath to 42 °C. Bring a vial of SOC medium or LB medium to room temperature. Warm selective plates to 37 °C for 30 minutes.
2. Thaw 100 µl of DB3.1 Chemically Competent Cell on ice. Aliquot 50 µl of cells into a pre-chilled 1.5 ml tube, then add target DNA (1-5 µl). Do not mix by pipetting up and down. Leave on ice for 30 minutes.
3. Heat-shock the cells for 45 seconds at 42 °C, without shaking. Immediately transfer to the tube to ice. Leave on ice for 2 minutes without shaking.
4. Add 500 µl of prewarmed SOC medium or LB medium (without antibiotics) into the tube. Mix well and shake at 37 °C for 1 hour at 200 RPM for cell recovery and expression of antibiotic resistance.
5. Spread 20-200 µl from each transformation vial onto a pre-warmed selective plate. Cells that have not been plated can be stored at 4 °C and plated the next day if required.
6. Invert the plates and incubate at 37 °C overnight.
7. Select colonies and analyse by restriction enzyme digestion, PCR or sequencing.

Note: