NEETZoologyBiotechnology and Its Applications
In mammals, including humans, insulin is synthesized as a pro-hormone which contains an extra stretch of polypeptide that must be removed to form the fully mature and functional hormone. Identify this extra stretch and choose the correct statement regarding its status in the genetically engineered insulin produced by the American company Eli Lilly.
Options
- AB-peptide; it is synthesized separately and then linked to the A-peptide using disulphide bonds.
- BC-peptide; it is synthesized along with the A and B chains but later removed by bacterial enzymes in vitro.
- CC-peptide; it is completely absent as the DNA sequences for only A and B chains were introduced into Escherich
- DC-peptide; it is required to facilitate the artificial linking of A and B chains during recombinant production
Correct answer
C. C-peptide; it is completely absent as the DNA sequences for only A and B chains were introduced into Escherich
Step-by-step solution
The pro-hormone in mammals contains an extra stretch of polypeptide called the C-peptide. This C-peptide is not present in the mature insulin and is removed during maturation into functional insulin. During the production of genetically engineered insulin by Eli Lilly, the major challenge was assembling insulin into a mature form. They solved this by preparing two separate DNA sequences corresponding only to the A and B chains of human insulin. These were introduced into Escherichia coli to produce the A and B chai