• Shruti Srivastava
• Arvind Kumar
• Surender Jangra
• Minhaj Ahmad Khan

E.colican use lactose as its sole carbon source. The E.colilacZ gene encodes the enzyme β-galactosidase that cleaves lactose into glucose and galactose. This is the first step in the catabolism of lactose in E.coli.Once the lactose is broken down, the glucose thus produced is able to enter glycolysis and produce the ATP through catabolism of glucose. Therefore, the lacZ gene is used by bacteria to metabolize and transport lactose into the cell as an energy source,The presence of lacZ gene in the plasmid also allows the transcription and translation of other proteins in the plasmid. For this purpose, the gene of interest is inserted just after the lacZ gene in the plasmid vector. This plasmid vector is then inserted in a bacterium that does not contain a lactase genome. When this bacterium is fed with lactose, then it will transcribe and translate the plasmid genome in order to survive. So while it is transcribing the lacZ gene, it also transcribes and translates the other gene that is inserted just after the lacZ gene.

"Isolation and Characterization of lac Z gene from Competitive Transformed cells of E.Coli DH5α Strain", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 1, page no.543-551, January 2019, Available :http://www.jetir.org/papers/JETIRDW06087.pdf

"Isolation and Characterization of lac Z gene from Competitive Transformed cells of E.Coli DH5α Strain", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 1, page no. pp543-551, January 2019, Available at : http://www.jetir.org/papers/JETIRDW06087.pdf