Routine protein expression competent cells

We offer a range of competent cells from Lucigen ideal for routine protein expression applications.

The highly efficient E. cloni® EXPRESS BL21(DE3) competent cells, provide high protein expression levels whilst  eliminating the need for plasmid transfer from cloning strain to expression. Available in both chemically competent  and electrocompetent formats,  these cells are suitable for use with any expression plasmid containing the T7 promoter.

The HI-Control™ chemically competent cells contain a plasmid with a constitutive lacI repressor gene . This provides tight control over promoters containing the lacO operator, enabling high protein yields with reduced leaky expression from small amounts of plasmid DNA. These cells are compatible with T7-lac and other lac-based promoters. 

Benefits of using these competent cells
• High protein expression levels
• Highest efficiency BL21(DE3) cells available - greater than 5 × 10⁹ cfu/µg 
• High protein yields - HI-Control 10G ≥1×10⁹ cfu/µg & HI-Control BL21(DE3) ≥1×10⁷ cfu/µg

Transformation efficiency comparison of commercially available BL21(DE3) competent cells

Cloning efficiencies are increased 25-1,000 fold relative to competitors’ preparations of BL21 cells, which is essential for construction of complex expression libraries. 

Comparison of cloning and protein expression procedures

The unprecedented transformation efficiency of E. cloni EXPRESS Electrocompetent Cells (> 5 × 109 cfu/µg) eliminates the need for plasmid transfer from the cloning strain to the expression strain, saving days of work in a typical cloning and expression experiment.

Material available for download
E. cloni EXPRESS Electrocompetent Cells manual
E. cloni EXPRESS Chemically Competent Cells manual
HI-Control BL21(DE3) & HI-Control 10G Chemically Competent Cells Manual