Which one of the following statements is correct about pro-hormones?

The correct answer is Option (1) → Pro-hormone needs to be processed before it becomes fully mature and functional.

A pro-hormone is the inactive first form in which a hormone is made. Like a pro-enzyme, it must be processed before it works. Insulin is the example. It is made as a pro-hormone that has an extra stretch called the C peptide. The C peptide is removed when insulin matures, leaving chains A and B joined by disulphide bridges. This was the main difficulty in making insulin by rDNA technology. The problem was solved by making chains A and B separately in E. coli and joining them.

(1) Pro-hormone needs to be processed before it becomes fully mature and functional. — Correct. This is what a pro-hormone is.

(2) Pro-hormones are already mature and functional. — Incorrect. This is the opposite. A pro-hormone is not yet functional.

(3) Pro-hormone needs to be exposed to sunlight to become functional. — Incorrect. A pro-hormone is activated by processing, that is, by removing a part of it, not by sunlight.

(4) Pro-hormone can not be processed in a laboratory. — Incorrect. Mature insulin has been made in the laboratory. Eli Lilly made the A and B chains separately and joined them into human insulin.

NCERT Extract:
Genetically Engineered Insulin – …