Question

How did Eli Lilly synthesis the human insulin ? Mention one difference between
this insulin and the one produced by the human pancreas.

Answer 1

Eli Lilly 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 in human pancreas is synthesised as a pro-hormone containing the C peptide, which is removed in mature hormone. The insulin synthesised by recombinant DNA technology did not contain C peptide and was prepared in the mature form.