BL21(DE3) chemically competent E.coli cells are suitable for transformation, high-level 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/Promoters: Ptac, Ptrc, Plac, PlacUV5, ParaBAD, PrhaBAD, T7
The transformation efficiency is ≥ 1x107 cfu/μg pUC19 plasmid DNA.
BL21 (DE3) chemically competent E. coli cells are supplied as a pack of 10 ready-to-use 100 μl/tube aliquots.
Electrocompetent BL21 (DE3) E.coli cells are also available.
Bulk quantities and custom packaging are available at very competitive prices for all Competent Cells.
Catalog # BL21-201
E. coli genotype: fhuA2 [lon] ompT gal (λ DE3) [dcm] ∆hsdS.
λ DE3 = λ sBamHIo ∆EcoRI-B int::(lacI::PlacUV5::T7 gene1) i21 ∆nin5
- Ideal for expressing proteins in E.coli.
- BL21(DE3) cells carry the lambda DE3 lysogen for expression from vectors utilizing the T7 promoter.
Storage: - 80°C. Thaw on ice only before use. Do not re-freeze.
Shipping: Product requires shipping on dry ice. Please contact email@example.com for shipment estimates.
This product is intended for LABORATORY RESEARCH USE ONLY. Not for diagnostic or therapeutic use.
Miroux B, Walker JE. Over-production of proteins in Escherichia coli: mutant hosts that allow synthesis of some membrane proteins and globular proteins at high levels. (1996) J. Mol. Biol. 260: 289.