Which of the following features are not a part of fully mature and fu…

The correct answer is Option (4) → (C) and (D) only

Mature insulin has two short polypeptide chains, chain A and chain B, joined by disulphide bridges. In mammals it is first made as a pro-hormone, which has an extra stretch called the C peptide. The pro-hormone has to be processed before it becomes mature, functional insulin.

(A) A peptide — A part of mature insulin. It is one of the two chains.

(B) B peptide — A part of mature insulin. It is the other chain, and it is joined to the A chain by disulphide bridges.

(C) C peptide — Not a part of mature insulin. It is the extra stretch that is removed during maturation.

(D) Pro-insulin peptide — Not a part of mature insulin. This is the precursor molecule (A and B chains with the C peptide). It is converted into insulin and is not a part of the final hormone.

NCERT Extract:
Genetically Engineered Insulin – “… Insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges (Figure 10.3). In mammals, including humans, insulin is synthesised as a pro-hormone (like a pro-enzyme, the pro-hormone also needs to be processed before it becomes a fully mature and functional 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.”