Competent Cells are prepared by Hanahan's method modified by Takara have a transformation efficiency of >1 x 108 cfu/ μ g when 100 μ l of the cells are transformed by 1 ng pBR322. As TaKaRa E.coli JM109 Competent Cells contains F' plasmid, it can be used as a host of M13 vector DNA as well as for preparation of DNA library or subcloning. When transformation of pUC vectors or transduction of M13 phage vector DNAs, recombinants can be selected easily by adding X-Gal and IPTG to a media utilizing the α -complimentarity to β -galactosidase of the competent cell.
