Millipore Sigma Vibrant Logo
Attention: We have moved. EMD Millipore products are no longer available for purchase on More

69053 BLR(DE3) Competent Cells - Novagen

View Products on
Purchase on Sigma-Aldrich


Replacement Information


Catalog NumberPackaging Qty/Pack
69053-3 Plastic ampoule 0.4 ml
69053-4 Glass bottle 1 ml
OverviewBLR is a recA- derivative of BL21 that improves plasmid monomer yields and may help stabilize target plasmids containing repetitive sequences or whose products may cause the loss of the DE3 prophage (1, 2).

DE3 indicates that the host is a lysogen of λDE3, and therefore carries a chromosomal copy of the T7 RNA polymerase gene under control of the lacUV5 promoter. Such strains are suitable for production of protein from target genes cloned in pET vectors by induction with IPTG.
Genotype: F- ompT hsdSB(rB- mB-) gal lac ile dcm Δ(srl-recA)::Tn10 (tetR)(DE3)

This product contains genetically modified organisms (GMO). Within the EU GMOs are regulated by Directives 2001/18/EC and 2009/41/EC of the European Parliament and of the Council and their national implementation in the member States respectively. This legislation obliges MilliporeSigma to request certain information about you and the establishment where the GMOs are being handled. Click here for Enduser Declaration (EUD) Form.

This product is sold for internal research use only. Any commercial use of this product, its components, and/or any derivatives thereof (including but not limited to proteins produced using the product or its components) (together and hereinafter the 'EMD Product') requires signature of a written commercial use agreement with EMD Millipore Corporation or its successor-in-interest. Commercial use shall include but not be limited to: (1) use of the EMD Product to manufacture products for sale to third parties; (2) use of the EMD Product to provide services, information, or data to third parties in exchange for consideration; (3) use of the EMD Product for therapeutic, diagnostic or prophylactic purposes (including as part of a device, chip, assay or other product); or (4) resale of the EMD Product, whether or not such EMD Product is resold for research use. Nothing contained herein shall be deemed to represent or warrant that additional third party rights are not required for use of the EMD Product. Please direct any questions on these use restrictions to:
Catalogue Number69053
Brand Family Novagen®
References1. A. Roca (U. of Wisconsin), personal

2. Studier, F. W. (1991) J. Mol. Biol. 219,
Product Information
0.4 ml1 mlComponent
2 × 0.2 ml5 × 0.2 mlBLR(DE3) Competent Cells
2 × 2 ml4 × 2 mlSOC Medium
2 ng2 ngTest Plasmid
Guaranteed efficiencyGuaranteed efficiency: > 2 x 10⁶ cfu/μg
Quality LevelMQ100
Biological Information
Physicochemical Information
Materials Information
Toxicological Information
Safety Information according to GHS
Safety Information
Product Usage Statements
Storage and Shipping Information
Ship Code Dry Ice Only
Toxicity Multiple Toxicity Values, refer to MSDS
Storage ≤ -70°C
Avoid freeze/thaw Avoid freeze/thaw
Do not freeze Ok to freeze
Packaging Information
Transport Information
Supplemental Information


BLR(DE3) Competent Cells - Novagen SDS


Safety Data Sheet (SDS) 

BLR(DE3) Competent Cells - Novagen Certificates of Analysis

TitleLot Number


Reference overview
1. A. Roca (U. of Wisconsin), personal

2. Studier, F. W. (1991) J. Mol. Biol. 219,


Express yourself


  • Mahmoud Reza Banki, Tillman U. Gerngross and David W. Wood. (2005) Novel and economical purification of recombinant proteins: Intein-mediated protein purification using in vivo polyhydroxybutyrate (PHB) matrix association. Protein Science 14, 1387-1395.
  • Gene L. Bidwell and Drazen Raucher. (2005) Application of thermally responsive polypeptides directed against c-Myc transcriptional function for cancer therapy. Molecular Cancer Therapeutics 4, 1076-1085.
  • Irina Bruck, Roxana E. Georgescu and Mike O'Donnell. (2005) Conserved interactions in the Staphylococcus aureus DNA polC chromosome replication machine. Journal of Biological Chemistry 280, 18152-18162.
  • Andrew Karla, et al. (2005) The identification of residues that control signal peptidase cleavage fidelity and substrate specificity. Journal of Biological Chemistry 280, 6731-6741.
  • Ken Okada and Toshiharu Hase. (2005) Cyanobacterial non-mevalonate pathway: (E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase interacts with ferredoxin in Thermosynechococcus elongatus BP-1. Journal of Biological Chemistry 280, 60672-20679.
  • Hisashi Yagi, et al. (2005) Amyloid fibril formation of α-synuclein is accelerated by preformed amyloid seeds of other proteins: Implications for the mechanism of transmissible conformational diseases. Journal of Biological Chemistry 280, 38609-38616.
  • Antonio Garofalo, et al. (2003) The FAR protein family of the nematode Caenorhabditis elegans. Differential lipid binding properties, structural characteristics, and developmental regulation. Journal of Biological Chemistry 278, 8065-8074.
  • Saloumeh Kadkhodayan, et al. (2000) Cloning, expression, and one-step purification of the minimal essential domain of the light chain of botulinum neurotoxin type A. Protein Expression and Purification 19, 125-130.
  • User Protocols

    TB009 Competent Cells
    TB053 Academic and Non-profit Laboratory Assurance Letter