How does human insulin formed using rDNA technique?

Steps involved in insulin production using rDNA technology:

a. The gene which are known to synthesise A and B poly peptide chains are isolated.

b. It is inserted in the plasmid of the E. Coli bacteria, at a site where gene for beta- glactosidase synthesis is present, using a DNA ligase enzyme.

c. Now as the plasmid synthesise beta galactosidase, it produces A & B polypeptide chains.

d. These A&B polypeptide chains are isolated and combined by disulphide bonds.