Mechanism of action of Penicillin

Mechanism of action of Penicillin

            Penicillin first binds with specific penicillin binding proteins (PBPs) that serves as drug receptor on bacteria. Then –

Ø  Penicillin acts as a selective inhibitor of transpeptidase enzyme . So the transpeptidation (cross-linking) reaction is inhibited and peptidoglycine synthesis is blocked. As a result a fragile cell membrane is formed and thus cell membrane permeability increased . Now fluid goes inside the cell due to hypertonic internal osmotic pressure . The bacterial cell becomes swollen and ultimately the cell explodes and lysed.

penicillin

Ø  Penicillin actives an autolytic enzyme by removing or inactivating the inhibitor  of autolytic enzyme in the cell wall – activated autolytic enzyme causes lysis of the bacterial cell wall in isotonic environment –Death  of the bacteria .