Question

Which of the following drugs used to treat influenza targets an enzyme?

• A. DNA polymerase
• B. Reverse transcriptase
• C. Neuraminidase
• D. Protease

Hint:

Neuraminidase inhibitors are most effective when given within 48 hours of influenza symptom onset.

Answer 1

The Correct Option is C

Influenza antiviral drugs target specific viral enzymes to inhibit replication and spread of the virus. Among the options: - DNA polymerase and reverse transcriptase are enzymes associated with DNA and retroviruses, respectively, not influenza viruses.
- Protease inhibitors are mainly used in treatment of HIV infections.
- Neuraminidase is a crucial enzyme on the surface of influenza viruses that facilitates the release of new viral particles from infected cells by cleaving sialic acid residues.
Neuraminidase inhibitors like oseltamivir and zanamivir block this enzyme, preventing viral spread and are thus effective anti-influenza agents.

Answer 2

The question asks which enzyme an anti-influenza drug targets. Influenza is an RNA virus, so start by ruling out enzymes that belong to other kinds of viruses before confirming the one that actually matters for influenza.

1. DNA polymerase: This enzyme copies DNA and is the target of drugs used against DNA viruses such as herpesviruses, for example acyclovir. Influenza is an RNA virus and does not depend on DNA polymerase, so this option is incorrect.
2. Reverse transcriptase: This enzyme converts viral RNA into DNA and is targeted by antiretroviral drugs used against HIV, a retrovirus. Influenza does not go through a DNA intermediate, so it has no reverse transcriptase to target, making this option incorrect.
3. Neuraminidase: This enzyme sits on the surface of the influenza virus and cleaves sialic acid residues so that newly made virus particles can detach from the infected cell and spread to new cells. Drugs such as oseltamivir and zanamivir block this enzyme, trapping new virions on the cell surface and stopping the infection from spreading, which makes this option correct.
4. Protease: Protease inhibitors are the mainstay of treatment for HIV, where the enzyme cleaves viral polyproteins into functional units. Influenza replication does not depend on this step, so this option is incorrect.

Only neuraminidase is an enzyme that influenza itself depends on for its life cycle, and it is the one current anti-influenza drugs are built to block.

Therefore, the correct answer is Neuraminidase.