Explain how insulin can be produced using recombinant DNA technology

Explanation

Steps to produce insulin using IDNA technology are :
(i) Two polypeptides chains (Chain - A with 21 amino acids, Chain - B with 30 amino acids) are interlinked through disulphide bridge. Insulin is synthesized as a prohormone which contains an extra stretch.
(ii) Restriction enzymes are used to produce nicks in insulin gene in E. coli plasmid at the same restriction sites producing sticky ends.
(iii) Mutant stains of E. coli is used to avoid bacteria attacking "foreign" genes.
(iv) Insert insulin gene next to E.coli in galactosidase gene which control transcription.
(v) Bacterial cells replicate and make copies of insulin gene.
(vi) Insulin protein is purified (beta-galactosidase removed)
(vii) Chains are mixed and disulphide bridges are formed.
(viii) Final product insulin is chemically identical to human insulin.