Thermo Scientific BL21(DE3) competent cells are suitable for non-toxic heterologous gene expression. This strain contains a λ DE3 prophage carrying the T7 RNA polymerase gene under the control of the lacUV5 promoter, enabling IPTG-induced expression of T7 RNA polymerase. BL21(DE3) is an E. coli B strain that does not contain the lon protease. It also lacks the outer membrane protease OmpT. The absence of these two key proteases reduces the degradation of heterologous proteins expressed in cells.

•High transformation efficiency: >1x10⁷ cfu/µg pUC19 DNA
• Specifically constructed for high-level recombinant protein expression
• Minimize RNA and protein Genetic markers for degradation
• Convenient to use, two reactions per bottle
• Contains SOC out-of-growth medium

Applications
BL21(DE3 ) Competent cells are suitable for T7 expression of high-level recombinant proteins.

Genotype
F– ompT hsdS_B (r _B–, m_B–) gal dcm (DE3)

Note: Not suitable for maintaining expression plasmids. Use DH10B or DH5α competent cells that do not carry the T7 RNA polymerase gene for plasmid DNA propagation (Cat. No. EC0112, EC0113).