What is the theory of antimetabolites based on?

• A. Blocking protein synthesis directly
• B. Using metabolic products as lead compounds
• C. Inhibiting cell wall synthesis
• D. Disrupting microtubule formation

Answer: (B)

Antimetabolites rely on structural similarity to the metabolites the cell normally uses. The idea is to take metabolic products as starting points (lead compounds) and modify them to create molecules that mimic substrates or cofactors closely enough to either compete with the real substrates for enzyme binding or become faulty intermediates. This disruption blocks essential biosynthetic pathways, such as nucleotide or folate metabolism, and impairs DNA/RNA synthesis and cell growth. That’s why using metabolic products as lead compounds is the best description of how antimetabolites work.

Other mechanisms described correspond to different drug actions: blocking protein synthesis, inhibiting cell wall synthesis, or disrupting microtubule formation are not the foundational strategy of antimetabolites.