JM109 is a K strain that is recA– and endA– to minimize recombination and improve the quality of plasmid DNA. Suitable for high efficiency transformation in a wide variety of applications.
JM109 Chemically Competent Cells
$120.00 – $265.00
Description
Intact Genomics JM109 Chemically Competent E. coli cells are suitable for high-efficiency transformation in a wide variety of applications such as cloning and sub-cloning.
Specifications
Competent cell type: Chemically Competent
Derivative of: E. coli K-12
Species: E. coli
Format: Tubes
Transformation efficiency: ≥1.0 x 108 cfu/µg pUC19 DNA
Blue/white screening: Yes
Shipping condition: Dry ice
Product Components & Storage
1) ig™ JM109 competent cells: -80 ºC
2) pUC19 control DNA: -20 ºC
3) Recovery medium: 4 ºC
Genomic Features
ig™ JM109 chemically competent cells have the following features:
- recA– and endA– to minimize recombination and improve the quality of plasmid DNA.
- Contains F’ episome for blue/white screening.
Genotype
endA1, recA1, gyrA96, thi, hsdR17 (rk–, mk+), relA1, supE44, Δ( lac-proAB), [F´ traD36, proAB, laqIqZΔM15].
Quality Control
Transformation efficiency is tested by using the pUC19 control DNA supplied with the kit and the high-efficiency transformation protocol listed below. Transformation efficiency should be ≥1 x 108 CFU/µg pUC19 DNA.
General Guidelines
Follow these guidelines when using JM109 Chemically Competent E. coli.
• Handle competent cells gently as they are highly sensitive to changes in temperature or mechanical
lysis caused by pipetting.
• Thaw competent cells on ice and transform cells immediately following thawing. After adding DNA,
mix by tapping the tube gently. Do not mix cells by pipetting or vortexing.
Calculation of Transformation Efficiency
Transformation Efficiency (TE) is defined as the number of colony forming units (cfu) produced by
transforming 1µg of plasmid into a given volume of competent cells.
TE = Colonies/µg/Dilution
Transform 1 µl of (10 pg/µl) pUC19 control plasmid into 50 µl of cells, add 950 µl of Recovery Medium. Dilute
10 µl of this in 990 µl of Recovery Medium and plate 50 µl. Count the colonies on the plate the next day. If
you count 100 colonies, the TE is calculated as follows:
Colonies = 100
µg of DNA = 0.00001
Dilution = 50/1000 x 10/1000 = 0.0005
TE = 100/.00001/.0005 = 2.0×1010