We will be conducting our annual physical inventory from March 11th through March 13th.

Orders received after 4pm CST on Tuesday, March 10th will be scheduled to ship as follows:

US Orders: Ship Saturday, March 14th for arrival on Monday, March 16th.
Canada Orders: Ship Monday, March 16th for arrival on Tuesday, March 17th.

Select items may ship earlier. For questions regarding the status of your order, contact custserv@promega.com.

E. coli Competent Cells Technical Bulletin

Instructions for Use of Product(s)
L1001, L1191, L1195, L2001, L2005, L2011, L2015

Literature # TB095

E. coli Competent Cells are prepared according to a modified procedure of Hanahan. The competent cells can be used for many standard molecular biology applications. JM109 competent cells are available for convenient transformation in two efficiencies: High Efficiency at greater than 108cfu/µg and Subcloning Efficiency at greater than 107cfu/µg. HB101 competent cells are available in high efficiency at greater than 108cfu/µg. JM109 cells are ideal hosts for many molecular biology applications. HB101 cells are useful for cloning in vectors that do not require α-complementation for blue/white screening. BL21(DE3)pLysS cells can be used with protein expression vectors that are under the control of the T7 promoter, such as pET vectors. This strain is lysogenic for lambda-DE3, which contains the T7 bacteriophage gene 1, encoding T7 RNA polymerase under the control of the lacUV5 promoter. BL21(DE3)pLysS also contains the pLysS plasmid, which carries the gene encoding T7 lysozyme. T7 lysozyme lowers the background expression level of target genes under the control of the T7 promoter but does not interfere with the level of expression achieved following induction with IPTG.

Summary of Changes
The following change was made to the 10/16 revision of this document:
1. Removed discontinued products.

Printed in USA. Revised 10/16.

Experienced User Protocols