Explain how human insulin is produced using recombinant DNA technique.

Insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges.

 In humans, insulin is synthesised as a pro-hormone with an extra stretch called the C peptide which is removed during maturation into insulin. The main challenge for production of insulin using rDNA techniques was getting insulin assembled into a mature form.

In 1983, Eli Lilly an American company prepared two DNA sequences corresponding to A and B, chains of human insulin and introduced them in plasmids of E. coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulphide bonds to form human insulin.

Insulin
Insulin