E.coli Competent Cells JM109 is a kind of competent bacteria with the ability to absorb exogenous DNA. It can be used for genetic recombination experiments. When using pUC series plasmid vectors for DNA transformation or M13 phage vectors for transfection, the LacZa polypeptide generated by the vector DNA and the LacZΔM15 encoded by JM09 are α-complemented to show β-galactosidase activity, which makes it easy to identify recombinant strains.
The JM109 E.coli competent cell kit includes 100 µl×10 and 50 µl×1 vials of cells stored at –80 °C for up to 12 months. The product contains control DNA (pUC19, 10 pg/µl) and provides detailed genotype information for the strain.
The manual outlines a ten‑step transformation protocol, from thawing on ice to recovery in SOC medium and overnight plating, and lists important precautions such as avoiding repeated freeze‑thaw cycles, using gentle mixing, and selecting appropriate tubes for heat shock. This manual is written in Chinese.
| Storage Temperature | -80 °C |
|---|---|
| Maximum Storage Time | 12 months |
| Packaging | 100 µl×10, 50 µl×1 |
| Control DNA | pUC19, 10 pg/µl |
| Transformation Efficiency | >1×10⁸ transformants per µg pUC19 |
| Genotype | recA1, endA1, gyrA96, thi-1, hsdR17, supE44, relA1, Δ(lac‑proAB)/F’[traD36, proAB+, lacIq, lacZΔM15] |
Store the cells at –80 °C and they remain viable for up to 12 months.
Thaw cells on ice, add DNA (≤10 ng), incubate on ice 30 min, heat‑shock at 42 °C for 30‑60 s, recover on ice, add pre‑warmed SOC medium, shake at 37 °C for 1 h, plate and incubate overnight at 37 °C.
Using 1 ng of plasmid DNA yields more than 1 × 10⁸ colonies per µg of pUC19.