DH5a competent cells

详情

DH5a competent cells CAT: DH***0 Price :  U.S.＄*8.*0 for **0ul;   $*3for 5***0ul;  $**5 for *0***0ul (negotiable)

Storage conditions: **5 ~ **5℃ storage, dry ice transportation.
 
Product description:
 
DH5α strain is the most commonly used competent cell in the laboratory. The lack of endonuclease (endA) improves the yield and quality of plasmid DNA; the recombinase defect (recA) reduces the probability of homologous recombination of the inserted fragment and ensures the stability of the inserted DNA; the presence of lacZΔM*5 makes DH5α suitable for blue-white screening. Our company's DH5α competent cells are made by special process, and the transformation efficiency is ≥**8cfu/μg using pUC*9 plasmid DNA detection.
 
Genotype
 
F- φ*0 lac ZΔM*5 Δ(lacZYA-arg F) U**9 endA1 recA1 hsdR*7(rk-,mk+) supE*4λ- thi *1 gyrA*6 relA1 phoA
 
Experimental process
 
1. Take out the competent cells from **0℃ and quickly put them on ice to melt.
 
2. Add the DNA to be transformed to **0 μl competent cells, flick the tube wall to mix (avoid using a gun to suck), and place on ice for *0 min.
 
3. After heat shock in a *2℃ water bath for *5 sec, quickly place on ice for 2 min. Do not shake the centrifuge tube.
 
4. Add **0 μl LB or SOC liquid culture medium (without antibiotics) to the centrifuge tube, mix well, and place in a *7℃, **0 rpm shaker for 1 h.
 
5. Centrifuge at 5,**0 rpm (2,**0 × g) for 3 min, discard **0 μl supernatant, resuspend the bacteria with the remaining culture medium, and evenly spread on the LB solid culture medium plate containing the corresponding antibiotics.
 
6. Place the plate upright in a *7℃ incubator for *0 min. After the bacterial solution is completely absorbed, invert the plate and culture overnight.
 
Notes:
 
1. After thawing in an ice-water bath, the competent cells should be used immediately. Leaving them for a long time will reduce the transformation efficiency.
 
2. The volume of DNA to be transformed should not exceed 1/*0 of the volume of competent cells.
 
3. After adding plasmid or ligation product, do not use a pipette to aspirate, just flick to mix.
 
4. Avoid repeated freezing and thawing of competent cells.