What is the role of the C peptide in insulin?

The correct answer is Option (2) → It is removed during maturation and helps in the formation of functional insulin.

Option (1) It helps insulin to bind receptors. — Incorrect. The C peptide is not present in mature insulin. Only mature insulin acts on the cells, so the C peptide cannot help it bind anything.

Option (2) It is removed during maturation and helps in the formation of functional insulin. — Correct. Insulin is first made as a pro-hormone, pro-insulin. Pro-insulin has chains A and B joined by an extra stretch, the C peptide. When the C peptide is cut out, the A and B chains stay linked by disulphide bridges, and this is the working insulin.

Option (3) It enhances the activity of mature insulin. — Incorrect. The C peptide is removed before insulin becomes mature, so it cannot act on mature insulin.

Option (4) It prevents the synthesis of insulin in the pancreas. — Incorrect. The C peptide is a part of the insulin that is made. It does not stop the making of insulin.

NCERT Extract:
Genetically Engineered Insulin – …