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Invitrogen™ MAX Efficiency™ DH5α Competent Cells
Description
Includes
Max Efficiency DH5α Competent Cells: 5 vials, 200μL each (total of 1mL), pUC19 DNA (0.01μg/mL): 1 vial, 100μL, S.O.C. medium: 2 bottles, 6mL each
MAX Efficiency™ DH5α Competent Cells are a well-known, versatile strain that is used in many everyday cloning applications. Prepared by a proprietary modification of the Hanahan method, these cells are suitable for high efficiency transformations in applications where low amount of DNA is used or to construct libraries using plasmid-derived vectors. In addition to supporting blue/white screening, recA1 and endA1 mutations in DH5α cells increase insert stability and improve the quality of plasmid DNA prepared from minipreps.
Benefits of MAX Efficiency DH5α Competent Cells:
• Versatile strain for everyday cloning applications
• High quality plasmid preparations
• Useful for generating plasmid libraries
DH5α competent cells for high transformation efficiency
The Φ80lacZΔM15 marker provides α-complementation of the β-galactosidase gene from pUC or similar vectors, and can be used for blue/white screening of colonies on bacterial plates containing Bluo-gal or X-gal. DH5α cells are capable of being transformed efficiently with large plasmids, and can also serve as a host for the M13mp cloning vectors if a lawn of DH5αF′IQ (Cat. No. 18288019) (or similar) is provided to allow plaque formation.
Features of MAX Efficiency DH5α Competent Cells include:
• Transformation efficiency of >1 x 109 transformants/μg plasmid DNA
• High plasmid yield from the DH5α (endA1) E. coli strain
• Blue/white screening capable (lacZΔM15)
• Greater insert stability (recA1)
Genotype:
F- Φ80lacZΔM15 Δ(lacZYA-argF) U169 recA1 endA1 hsdR17 (rk-, mk+) phoA supE44 λ-thi-1 gyrA96 relA1
Find the strain and format that fits you needs
• DH5α strain and its derivatives available in with a variety of transformation efficiencies and in both electrocompetent and chemically competent formats.
• ElectroMAX™ DH5α-E Competent Cells (Cat. No. 11319019) are engineered for electroporation to achieve high transformation efficiency of >1 x 1010.
• DH5α T1R competent cells are available in MultiShot format for high throughput applications.
Order Info
Shipping Condition: Dry Ice
Specifications
Specifications
| Product Type | Chemically Competent Cells |
| Contains F' Episome | No |
| Improves Plasmid Quality | Yes (endA1) |
| Cloning Methylated DNA | No |
| Transformation Efficiency Level | High Efficiency (>1 x 109 cfu/μg) |
| Content And Storage | • Max Efficiency DH5α Competent Cells (5 x 200 μL) Store Competent Cells at –80°C. • pUC19 DNA (100 μL at 0.01 μg/mL) Store pUC19 DNA at –20°C. • S.O.C. Medium (2 x 6 mL) Store S.O.C. Medium at 4°C or room temperature. |
| Antibiotic Resistance Bacterial | No |
| Cloning Unstable DNA | Not suitable for cloning unstable DNA |
| Blue/White Screening | Yes (lacZΔM15) |
| High-throughput Compatibility | Low |
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Frequently Asked Questions (FAQs)
If the insert is potentially toxic to the host cells, here are some suggestions that you can try:
- After transforming TOP10 or DH5? cells, incubate at 25-30°C instead of 37°C. This will slow down the growth and will increase the chances of cloning a potentially toxic insert.
- Try using TOP10F' cells for the transformation, but do not add IPTG to the plates. These cells carry the lacIq repressor that represses expression from the lac promoter and so allows cloning of toxic genes. Keep in mind that in the absence of IPTG, blue-white screening cannot be performed.
- Try using Stbl2 cells for the transformation.
For best results, DNA used in electroporation must have a very low ionic strength and a high resistance. A high-salt DNA sample may be purified by either ethanol precipitation or dialysis.
The following suggested protocols are for ligation reactions of 20ul. The volumes may be adjusted to suit the amount being prepared.
Purifying DNA by Precipitation: Add 5 to 10 ug of tRNA to a 20ul ligation reaction. Adjust the solution to 2.5 M in ammonium acetate using a 7.5 M ammonium acetate stock solution. Mix well. Add two volumes of 100 % ethanol. Centrifuge at 12,000 x g for 15 min at 4C. Remove the supernatant with a micropipet. Wash the pellet with 60ul of 70% ethanol. Centrifuge at 12,000 x g for 15 min at room temperature. Remove the supernatant with a micropipet. Air dry the pellet. Resuspend the DNA in 0.5X TE buffer [5 mM Tris-HCl, 0.5 mM EDTA (pH 7.5)] to a concentration of 10 ng/ul of DNA. Use 1 ul per transformation of 20 ul of cell suspension.
Purifying DNA by Microdialysis: Float a Millipore filter, type VS 0.025 um, on a pool of 0.5X TE buffer (or 10% glycerol) in a small plastic container. Place 20ul of the DNA solution as a drop on top of the filter. Incubate at room temperature for several hours. Withdraw the DNA drop from the filter and place it in a polypropylene microcentrifuge tube. Use 1ul of this DNA for each electrotransformation reaction.
There are a few exceptions, but in general the difference is in guaranteed transformation efficiency as follows:
Subcloning Efficiency cells are guaranteed to produce at least 1.0 x 10E6 transformants per µg of transformed pUC19 or pUC18 supercoiled plasmid
Library Efficiency cells are guaranteed to produce at least 1.0 x 10E8 transformants per µg pUC19 or pUC18 DNA
MAX Efficiency cells are guaranteed to produce at least 1.0 x 10E9 transformants per µg pUC19 or pUC18 DNA
The main advantage is that TOP10 cells have mutations in the mcrA, mcrB and mrr genes which encode restriction systems for methylated DNA. This means that you can clone highly methylated DNA derived from such sources as mammalian and plant cells, and it will not be degraded after transformation.
Yes, several of our competent cells products are frozen with DMSO. The presence of DMSO (dimethylsulfoxide) will generally be indicated in the MSDS files if you have a question about a particular product, but here is a list of commonly used products that are known to have DMSO in the freezing buffer:
One Shot OmniMAX 2 T1 Phage Resistant Cells, Cat. No. C8540-03
One Shot INV?F' Chemically Competent Cells, Cat. No. C2020-03 and C2020-06
One Shot MAX Efficiency DH5?-T1 Chemically Competent Cells, Cat. No. 12297-016
MAX Efficiency DH5?-T1 Phage Resistant Cells, Cat. No. 12034-013
MAX Efficiency DH5? Chemically Competent Cells, Cat. No. 18258-012
Library Efficiency DH5? Chemically Competent Cells, Cat. No. 18263-012
MAX Efficiency DH5? F'IQ Cells, Cat. No. 18288-019
MAX Efficiency Stbl2Chemically Competent Cells, Cat. No. 10268-019
For Research Use Only. Not for use in diagnostic procedures.