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Promega Corporation

BL21(DE3)pLysS Competent Cells

BL21(DE3)pLysS Competent Cells allow high-efficiency protein expression of any gene that is under the control of a T7 promoter and has a ribosome binding site. BL21(DE3)pLysS is lysogenic for λ-DE3, which contains the T7 bacteriophage gene I, encoding T7 RNA polymerase under the control of the lac UV5 promoter. BL21(DE3)pLysS also contains a plasmid, pLysS, which carries the gene encoding T7 lysozyme. T7 lysozyme lowers the background expression level of target genes under the control of the T7 promoter but does not interfere with the level of expression achieved following induction by IPTG. For researchers doi...

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Single-Use BL21(DE3)pLysS Competent Cells

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Single-Use BL21(DE3)pLysS Competent Cells


  • Single-Use BL21(DE3)pLysS Competent Cells

    L119B20 x 50μl
(20 × 50µl)
- L1195 $ 196.00 Add to cart

BL21(DE3)pLysS Competent Cells, >106cfu/μg

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BL21(DE3)pLysS Competent Cells, >106cfu/μg


  • Competent Cells Control DNA

    L107A1 x 30μl
  • BL21(DE3)pLysS Competent Cells, >106cfu/μg

    L119A5 x 200μl
(5 × 200µl)
- L1191 $ 160.00 Add to cart

Storage Conditions

Store at –70°C.

For product intended use please see Patents & Disclaimers tab.

Use Restrictions

L1195, L1191 For Research Use Only. Not for Use in Diagnostic Procedures.

Patents - Disclaimers

L1195, L1191 Usage Restrictions for the T7 Expression System
The T7 expression system is based on technology developed at Brookhaven National Laboratory under contract with the U.S. Department of Energy and is the subject of patents assigned to Brookhaven Science Associates, LLC (BSA). This technology, including bacteria, phage and plasmids that carry the gene for T7 RNA polymerase, is to be used for academic or nonprofit laboratory or licensed commercial research purposes only. By accepting or using the T7 expression technology you agree to be bound by the following conditions set forth by BSA. The initial purchaser may refuse to accept the conditions of this notice by returning this product and the enclosed materials to Promega unused.

Academic and NonProfit Laboratories
No materials that contain the cloned gene for T7 RNA polymerase may be distributed further to third parties outside of your laboratory unless the recipient receives a copy of this assurance notice and agrees to be bound by its terms. This limitation applies to Bacterial Strains JM109(DE3), BL21(DE3)pLysS and KRX and to any derivatives thereof.

Commercial Laboratories
A license is required for any commercial use of the T7 expression system, including use of the T7 system for research purposes or for production purposes by any commercial entity. Information about commercial licenses may be obtained from the Licensing Office, Brookhaven National Laboratory, Upton, NY 11973, Telephone: 631-344-7134, FAX: 631-344-3729.

L1195, L1191 Usage restrictions apply to Bacterial Strains JM109(DE3), BL21(DE3)pLysS and KRX and to any derivatives thereof.

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