Question

Which of the following is an incorrect statement?

• A. Fifty–one amino acids are present in completely mature insulin.
• B. Insulin used for diabetes was earlier extracted from the pancreas of slaughtered cattle and pigs.
• C. In humans, insulin is synthesised as a prohormone.
• D. The mature insulin has three peptides, chains A, B, and C.

Answer 1

Answer: (D)

Mature insulin consists of two polypeptide chains, A and B consisting of 21 and 30 amino acids respectively. These A and B chains are linked together by disulphide bonds.

The proinsulin contains an extra stretch called c-protein which is removed during maturation.