Identify the correct sequence of steps involved in the production of recombinant insulin.
A. Production of chain A and B separately
B. Introduction of chain A and B DNA into E. coli
C. Preparation of DNA sequences of chain A and B of insulin
D. Combining the chain A and B through disulfide bonds to form recombinant insulin
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → C, B, A, D
C. Preparation of DNA sequences of chain A and B of insulin — first. Insulin is made of two short polypeptide chains, A and B, joined by disulfide bridges. In 1983, the American company Eli Lilly prepared two DNA sequences, one for each chain of human insulin.
B. Introduction of chain A and B DNA into E. coli — second. The two DNA sequences were put into plasmids of E. coli, so that the bacteria would make the insulin chains.
A. Production of chain A and B separately — third. The bacteria produced chains A and B separately, and the chains were then extracted.
D. Combining the chain A and B through disulfide bonds to form recombinant insulin — last. The two chains were joined by creating disulfide bonds to form human insulin. This avoided the problem of turning the pro-hormone (which carries an extra C peptide) into mature insulin.
NCERT Extract:
Genetically Engineered Insulin – “… In 1983, Eli Lilly an American company 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. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin.”