dam- dcm- Bacteriophage T1-Resistant - Discontinued

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Methyltransferase deficient chemically competent cells that are an ideal host to generate plasmid DNA lacking in dam and dcm methylation.

Features & Benefits

  • Lack dam and dcm methylases -allowing more options in choice of restriction enzymes.
  • T1-Resistant -protects cells from bacteriophage infection
  • Efficient -available in ≥107 cfu/μg, for routine subcloning
  • Convenient size -small aliquots reduce waste


  • Generate plasmid DNA devoid of dam and dcm methylation
  • Enable restriction digestion of plasmid DNA by methylation-sensitive endonucleases
  • Stud methylation on expression or DNA repair


dam-/dcm- Chemically Competent Cells are an ideal host to generate plasmid DNA lacking in dam and dcm methylation. The absence of dam and dcm methylases in this strain prevents methylation at GATC and CC(A/T)GG sites, respectively. Plasmid DNA propagated and purified from this host can be digested by the many restriction enzymes otherwise inhibited by dam or dcm methylation.

A dam/recA double mutation is lethal, so the parent strain is recA+. This can increase mutation rate in the cell and reduce transformation efficiency. This product is therefore not a suitable cloning host. Instead, DNA should be maintained in a dam+ strain unless there is a specific need for DNA free of Dam or Dcm methylation.


Genotype: F- dam-13:Tn9(CamR) dcm-6 ara-14 hisG4 leuB6 thi-1 lacY1 galK2 galT22 glnV44 hsdR2 xylA5 mtl-1 rpsL 136(StrR) rtbD1 tonA31 tsx78 mcrA mcrB1




Chemically Competent Cells

10 x 100µl

pUC19 control vector (10pg/µl)


Storage & Stability

All kit components should be stored at -80°C upon receipt.

When stored under the recommended conditions and handled correctly, full activity of the kit is retained until the expiry date on the outer box label.

Shipping conditions

Shipped on dry/blue ice.

Other researchers use:

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