HIT™-21 are unique chemically competent cells, which utilize a novel transformation protocol, High Ice Transformation. A simple ice incubation from 1-10 minutes is all that is required to transform the cells to high efficiency. There is no requirement for heat shock or a recovery step.


Efficiency Levels

Each HIT™ shipment is -70^oC electronically monitored and recorded for maximum efficiency guarantee.


HIT™ Value 10⁸

• Minimum efficiency is 5 x 10⁷ transformations/µl pUC19


• Average efficiency is 1 x 10⁸ transformations/µl pUC19


• Recommended for protein expression only

The HIT™-21 is the most popular E. coli strain worldwide for protein production. This stain is inducible by IPTG, incorporating the popular T7 RNA polymerase gene under the tight control of the lacUV5 promoter for high expression. The ion intracellular and OmpT extra cellular protease deficiencies ensure high volumes of protein generation. This strain is not suitable for toxic proteins. However, the improve the viability and growth characteristics of the cell for no-toxic protein production.

HIT™-21 genotype: E. coli B F-dc, ompT jsd5(rB - mB) gal (DE3)

N.B. Invitrogen products use Heat Shock and take two hours. Ours use High Ice Transformation and take 1-10 minutes. Cells are more viable because there is no Heat Shock.