Explain the steps involved in the production of genetically engineered insulin.

Explanation

Insulin used for diabetes was earlier extracted from pancreas of slaughtered cattle and pigs. Insulin consists of two short polypeptide chains, chain A and chain B that are linked together by disulphide bridge.
In mammals, including humans, insulin is synthesised as a pro hormone which contains an extra stretch called the C peptide. This C peptide is not present in the mature insulin and 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 1993 Eily Lilly an American company prepared two DNA se quences corresponding to A and B, chain of human insulin and intro duced them in plasmid of E.coli to produce insulin chains, chain A and B were produced separately, extracted and combined by creating disulphide bonds to form human insulin.