Read the paragraph given below and answer the question.

Insulin used for diabetes was earlier extracted from slaughtered cattle and pigs. Insulin from an animal source, though caused some patients to develop allergy or other type of reactions. Insulin consists of two short polypeptide chains: chain A and chain B, that are linked bridges. In mammals, including human, insulin is synthesised as a pro-hormone.

Bonds which link 'A' and 'B' peptide chains of human insulin are

Disulfide

The correct answer is Option (2) → Disulfide

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

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.