Penicillin Mechanism — NDEB AFK MCQ

Correct answer: C — Inhibition of bacterial cell wall synthesis by blocking transpeptidase (PBPs)

Penicillin V inhibits bacterial cell wall synthesis by irreversibly binding to penicillin-binding proteins (PBPs/transpeptidases), which are enzymes that catalyse the final cross-linking step of peptidoglycan synthesis. Without intact peptidoglycan, the bacterial cell wall is weakened and the bacterium undergoes osmotic lysis. Penicillin V is the oral form preferred for dental infections in some jurisdictions, though amoxicillin is more commonly used in Canada due to better absorption and broader spectrum.

Reference: Katzung – Basic and Clinical Pharmacology, 15th ed., 2021