Step 1: Understanding the Concept:
This question tests which viral enzyme influenza drugs are designed to block, so the first job is to place each enzyme in the options with the correct virus family.
Step 2: Key Formula or Approach:
Match enzyme to virus type: DNA polymerase belongs to DNA viruses, reverse transcriptase and protease belong to retroviruses like HIV, and neuraminidase belongs to the influenza virus surface.
Step 3: Detailed Explanation:
Influenza is an RNA virus with two key surface proteins, hemagglutinin and neuraminidase.
Hemagglutinin lets the virus attach to and enter a host cell, while neuraminidase cleaves sialic acid so newly formed viral particles can be released and spread to new cells.
Drugs such as oseltamivir and zanamivir are built to fit into the active site of neuraminidase and block this release step.
DNA polymerase, reverse transcriptase, and protease belong to other virus families and play no part in the influenza life cycle.
Step 4: Final Answer:
The enzyme targeted by anti-influenza drugs is neuraminidase.