Read the given passage and answer the following questions :

Managing diabetes is possible by administering insulin periodically. Insulin used for diabetes was earlier extracted from pancreas of slaughtered cattle and pigs. However, this insulin caused some people to develop allergies and other types of reactions. In mammals, including humans, insulin is synthesized as a prohormone and is later converted to insulin. Insulin used for diabetes was earlier extracted from pancreas of slaughtered cattle and pigs. Insulin from an animal source, though caused some patients to develop allergy or other types of reactions to the foreign protein. Insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulfide bridges .

Identify A and B in the picture.

A: Proinsulin

B: Chain C

The correct answer is Option (2)-

A: Proinsulin

B: Chain C

Insulin is used for diabetes treatment. Insulin is composed of two short polypeptide chains, namely chain A and chain B, which are connected by disulfide bridges.

In mammals, including humans, insulin is initially produced as a prohormone, similar to a proenzyme that requires processing to become a fully mature and functional hormone. This prohormone contains an additional segment called the C-peptide. However, during the maturation process into insulin, the C-peptide is removed, and it is not present in the mature insulin.

The main challenge in producing insulin using recombinant DNA (rDNA) techniques was achieving the assembly of insulin into its mature form. In 1983, the American company Eli Lilly prepared two DNA sequences corresponding to the A and B chains of human insulin and introduced them into plasmids of Escherichia coli (E. coli) bacteria to produce insulin chains. The A and B chains were generated separately, extracted, and then combined by creating disulfide bonds to form human insulin. This process allowed for the production of synthetic human insulin through rDNA technology, providing a safer and more reliable source of insulin for diabetes management.

         Maturation of pro-insulin into insulin