Oral Protein Pharmaceuticals — NEET Biology

Correct answer: B — S3 and S4 only

Let's evaluate each statement: - **S1. Insulin extracted from the pancreas of slaughtered animals is structurally identical to human insulin.** This statement is NOT correct. Animal insulin is 'similar' but not 'structurally identical' to human insulin, which caused 'allergy or other types of reactions to the foreign protein' in some patients. - **S2. Recombinant DNA technology ensures that therapeutic drugs like insulin are free from immunological responses when derived from non-human sources.** This statement is NOT correct. Recombinant therapeutics are safe and effective because they are 'identical to human proteins' and thus 'do not induce unwanted immunological responses'. If they were derived from non-human sources (meaning, they *are* non-human proteins), they could cause immunological responses. The key is that recombinant human insulin *is human* (structurally identical), even though produced in a non-human organism like E. coli. - **S3. The primary challenge in producing recombinant human insulin was assembling the A and B chains into a mature, active form.** This statement is CORRECT. NCERT states, 'The main challenge for production of insulin using rDNA techniques was getting insulin assembled into a mature form.' This was overcome by producing chains A and B separately and then combining them. - **S4. Orally administered insulin is generally not effective due to the protein's digestion by gastrointestinal enzymes.** This statement is CORRECT. The NCERT text asks the reader to 'Think about whether insulin can be orally administered... Why?' The implication is that, being a protein, it would be digested in the alimentary canal before reaching its target, hence not effective. - **S5. Eli Lilly's method for recombinant insulin involved producing pro-insulin in E. coli, followed by its maturation.** This statement is NOT correct. Eli Lilly prepared two DNA sequences corresponding to A and B chains, produced them separately in E. coli, extracted them, and then combined them by creating disulfide bonds *in vitro* to form human insulin. They did not produce pro-insulin in E. coli and then mature it. Therefore, statements S3 and S4 are correct. Option B correctly identifies S3 and S4 as correct. Options A, C, and D include incorrect statements. The question tests understanding of the advantages of recombinant insulin, challenges in its production, and general considerations for protein-based therapeutics.