HI-Control™ Competent Cells

The HI-Control™ strains are based on the popular E. cloni 10G (same as DH10B) and BL21(DE3) strains. They were created by adding a plasmid bearing a constitutive lacI gene, which provides tight control over promoters containing the lacO operator.

Reduce leaky expression: The LacI repressor protein binds to the lacO operator to block transcription of downstream genes. In the absence of an induction agent such as lactose sugar or IPTG, target protein expression from the adjacent promoter will be greatly reduced.

High protein yields: Both 10G and BL21(DE3)-based strains are noted for their ability to express high levels of protein. For expression from a T7 promoter please select the HI-Control BL21(DE3) strain. This strain also is deficient in proteases, yielding more stable protein preparations. Most other promoters can be used in either HI-Control strain.

Terrific efficiency: The simple, reliable heat-shock procedure for chemical transformation gives excellent results from small amounts of plasmid DNA.

Excellent value: HI-Control competent cell kits include control DNA and Recovery Medium, and are priced for everyday convenience.