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BL21(DE3) Electrocompetent Cells

for protein expression



for molecular biology

cell transformation

competent cell type: electrocompetent
transformation efficiency: ≥5 × 109 cfu/μg

shipped in

dry ice

storage temp.


General description

The BL21(DE3) Electrocompetent Cells are the first to offer high efficiency cloning and high level protein expression in the same cell.
Cloning efficiencies are increased 25-1,000 fold relative to other preparations of BL21 cells, which is essential for construction of complex expression libraries.


F – ompT hsdSB (rB- mB-) gal dcm (DE3)

Features and Benefits

The unprecedented transformation efficiency of the BL21(DE3) 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


  • BL21(DE3) electrocompetent cells
  • pUC 19 transformation control DNA
  • recovery medium for expression

Storage Class Code

10 - Combustible liquids



Certificate of Analysis

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Certificate of Origin

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Bacterial Transformation

Bacterial transformation is a process of horizontal gene transfer by which some bacteria take up foreign genetic material (naked DNA) from the environment. Bacteria that can take up free, extracellular genetic material are known as competent cells.


BL21(DE3) Electrocompetent Cells

BL21(DE3) Electrocompetent Cells are provided in 25 μL aliquots, sufficient for one reaction. Transformation is carried out in a 0.1 cm gap cuvette. Optimal settings for electroporation are listed in the table below. Note that alternate settings result in transformation efficienes about 20-50% lower. Typical time constants are 3.5 to 4.5 msec.

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

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