HI-Control® BL21(DE3) Chemically Competent Cells

HI-Control® BL21(DE3) Chemically Competent Cells




12 rxns (SOLOs)


-80º C


HI-Control™ BL21(DE3) and HI-Control™ 10G Competent Cells




  • Induce high level protein expression from lac based promoters (T7, T5-lac, tac, trc, lac)
  • Tightly regulate expression from T7 promoters with HI-Control BL21(DE3) Chemically Competent Cells
  • Clone targets and reduce background protein expression with HI-Control 10G Chemically Competent Cells

The HI-Control™ strains are based on E. cloni10G ( DH10B) and BL21(DE3) strains. These strains harbor a plasmid bearing a constitutivelacI repressor gene, which provides tight control over promoters containing thelacO operator.

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

Obtain high protein yields: Both 10G and BL21(DE3)-based strains express high levels of protein. For expression from a T7 promoter, select the HI-Control BL21(DE3) strain. Other lac-based promoters like T5-lac, tac, trc, and lac, can be used in either HI-Control strain.

Achieve high efficiency transformations:  Highly efficient competent cells give excellent results from small amounts of plasmid DNA. 

  Tightly Control Protein Expression    
  T7 Promoters Non-T7 lac promoters 
(T5-lac, tac, trc, lac)
Clone with low background target expression Transformation efficiencies
      ≥ 1×107 cfu/µg
      ≥ 1×109 cfu/µg


HI-Control™ BL21 (DE3): F- ompT hsdSB (rB- mB-) gal dcm (DE3) Mini-F lacIq1(GentR)

HI-Control™ 10G: mcrA Δ(mrr-hsdRMS-mcrBCendA1 recA1 ?80dlacZΔM15 ΔlacX74 araD139 Δ (ara,leu)7697 galU galK rpsL (StrR) nupG λ− tonA Mini-F lacIq1 (GentR)


  • Ordering

  • Specifications

  • Manuals

  • Resources

Contact your local distributor for pricing
Product Description Size Cat. No.
HI-Control™ 10G Chemically Competent Cells (SOLOs)   12 rxns (SOLOs) 60110-1
HI-Control™ BL21(DE3) Chemically Competent Cells (SOLOs)   12 rxns (SOLOs) 60435-1
Competent Cells include Control DNA and Recovery Medium, and are packaged as SOLOs (1 transformation per tube). Recovery Medium is also available separately. The specified transformation efficiencies are with pUC DNA, unless indicated otherwise.