Q172 / 180 · AIIMS 2018 (27 May) · Zoology

Assertion : Eli Lily prepared two DNA sequences corresponding to $\mathrm{A}$ and $\mathrm{B}$ chain of human insulin and introduced them in the plasmid of E.coli to produce polypeptide chains of insulin. Reason : Chains A and B were produced separately, extracted and combined by creating disulphide bonds to form human insulin.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion.
  • Correct answer
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion.
  • C
    If assertion is true but reason is false.
  • D
    If both assertion and reason are false.

Solution

Insulin is synthesised as a prohormone which contains an extra stretch called C peptide. This C peptide is not present in the mature insulin as it is removed during maturation. The main challenge for insulin production using rDNA technique was getting insulin assembled into a mature form. In 1983, Eli Lily, an American company, first prepared two DNA sequences corresponding to $A$ and $B$ chains of human insulin and introduced them in plasmids of $E$. coli to produce insulin chains. Chain A and B were produced separately, extracted and combined by creating disulphide bonds to form human insulin.

Hence, the correct answer is option: 'B'.

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