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DH5-alpha and BL21DE3 Chemically Competent E.coli Cells |

Amid Biosciences

Combo Pack of AB 5-alpha and BL21(DE3) Chemically Competent E.coli Cells

$ 200.00

This Chemically Competent E.coli Cells Combo Pack allows fulfilling your cloning and protein expression needs. The Combo Pack contains 5 tubes of AB 5-alpha and 5 tubes of BL21(DE3) chemically competent E. coli cells in convenient packaging format (100 μl/tube aliquots).

AB 5-alpha cells are directly comparable to DH5a™ cells. These cells are perfect for use in all cloning applications, including preparation of high-quality plasmid DNA. They offer efficient transformation even with large plasmids.

The transformation efficiency is  ≥ 1x108 cfu/μg pUC19 plasmid DNA.


  • Transformation of plasmids into bacterial cells
  • Cloning, sub-cloning, library construction
  • Blue/white color screening

Catalog # CAB5BL21-201

Genotype: F- deoendA1 recA1 relA1 gyrA96 hsdR17(rk-, mk+) supE44 thi-1 phoA Δ(lacZYA-argF)U169 Φ80lacZΔM15 λ-

BL21(DE3) chemically competent E.coli cells are suitable for transformation, high-level protein expression and production of recombinant proteins in bacterial systems. The strain lacks the lon and ompT proteases thus promoting stability of recombinant proteins. BL21(DE3) strain carries a copy of the T7 RNA polymerase under control of the IPTG inducible lacUV5 promoter, and as a result, is ideal for controlled expression of both E. coli and T7 promoter driven constructs.  

Compatible Expression Vectors/PromotersPtac, Ptrc, Plac, PlacUV5, ParaBAD, PrhaBAD, T7 

The transformation efficiency is  ≥ 1x106 cfu/μg pUC19 plasmid DNA.


  • Ideal for expressing proteins in E. coli.
  • BL21(DE3) cells carry the lambda DE3 lysogen for expression from vectors utilizing the T7 promoter.

Genotype: fhuA2 [lon] ompT gal (λ DE3) [dcm] ∆hsdS.

λ DE3 = λ sBamHIo ∆EcoRI-B int::(lacI::PlacUV5::T7 gene1) i21 ∆nin5

Storage:  -80°C. Thaw on ice only before use. Do not re-freeze.

Shipping:  Product requires shipping on dry ice. Please contact for shipment estimates. 


This product is intended for LABORATORY RESEARCH USE ONLY. Not for diagnostic or therapeutic use.

AB 5-alpha Transformation Protocol

BL21(DE3) Transformation Protocol

Bulk quantities and custom packaging are available at very competitive prices for all Competent Cells. 

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