Question

the cdna for human insulin is cloned into an expression plasmid under control of the lac operon promoter/operator region. the plasmid is then transformed into e. coli. what would you need to add in order to generate the human insulin protein in this strain?

Answer 1

To produce human insulin in E. coli with a cloned insulin cDNA, lactose or IPTG must be added to induce the lac operon, enabling transcription and subsequent production of insulin. This recombinant DNA technology has been pivotal for diabetic treatment.

Step-by-step explanation:

To generate human insulin protein in the E. coli strain containing the expression plasmid with the cloned cDNA for human insulin under the control of the lac operon promoter/operator region, you would need to add lactose or isopropyl β-D-1-thiogalactopyranoside (IPTG). Lactose or IPTG would induce the lac operon, allowing transcription of the human insulin gene. The E. coli would then translate the mRNA into the A and B polypeptide chains, which can be processed to form active insulin. It's crucial to ensure the presence of necessary machinery for post-translational modifications if those are required for insulin maturation.

This recombinant DNA technology approach for manufacturing human insulin, known as humulin, has made the treatment for diabetes more effective and reduced the occurrence of allergic reactions that were common when pig insulin was used.