Final answer:
The drug that deactivates the active site of certain viral enzymes to prevent the destruction of host cell proteins is called an enzyme inhibitor.
Step-by-step explanation:
The drug that deactivates the active site of certain viral enzymes to prevent the destruction of host cell proteins is called enzyme inhibitor. This drug blocks the active site of the viral protease enzyme, preventing the virus from breaking down host proteins and gaining entry into the host cell. By blocking the active site, the drug prevents the virus from destroying the host cells.