Please find below the link and abstract for the following protocol:
http://www.promega.com/tbs/tb092/tb092.html
Abstract for E. coli S30 Extract System for Circular DNA
The E. coli S30 Extract for Circular DNA simplifies the transcription/translation of DNA sequences cloned in plasmid or lambda vectors, providing a powerful tool for identifying and characterizing polypeptides. The investigator needs only to supply the cloned DNA containing a good E. coli promoter and ribosome binding sites. Promegas S30 Extract for Circular DNA Templates is prepared by modifications of the method described by Zubay from an E. coli strain B deficient in OmpT endoproteinase and lon protease activity. This results in a greater stability of expressed proteins that would otherwise be degraded by proteases if expressed in vivo. The S30 in vitro system also allows higher expression levels of proteins that are normally expressed at low levels in vivo due to the action of host-encoded repressors.
Expression of the luciferase gene in the S30 System for Circular DNA can be easily assayed by non-radioactive methods using the provided Luciferase Assay System. The assay reaction produces high light output for several minutes, allowing the researcher to choose from several methods of detection, including simple visual observation of luminescence.