Two chains of DNA sequence corresponding to A and B chains of human insulin prepared, introduced them into plasmids of E. coli to produce separate A and B chains, A and B chains extracted combined by creating disulphide bonds.
Detailed Answer :
American Company Eli Lilly used the knowledge of r-DNA technology to produce human insulin in the following way.
1. Preparation of DNA corresponding to A and B chain separately.
2. Extraction of plasmid from bacteria.
3. Insertion of DNA corresponding to A and B chain separately in plasmid.
4. Transforming the bacteria with this recombinant plasmid.
5. Expression of the desired product from this DNA .
6. Purication of A and B chain.
7. Linking them with disulde bonds so that they act as human insulin.