Question

Explain in detail the mechanism of action for penicillin. The Antimicrobials and their Mechanisms table provided to you says that the mechanism of action for penicillin is "block cross linking." Elaborate on the table description. What is cross linked? What is being blocked? What force actually kills an affected bacterial cell? HTML Editor D

Answer 1

Ans:

Penicillin is the antibiotics discovered by Alexander Fleming from Penicillium notatum. This penicillins share a common fused bicyclic nucleus of $\beta$ -lactam and thiazolidine rings. Transpeptidase is the important enzyme of bacterial cell wall synthesis. The $\beta$ -lactam rings of penicillin binds to the transpeptidase enzyme and inhibits transpeptidation reaction and its cross-linkig activity that leads to osmotic lysis. So, new cell wall formation is prevented and the bacterial cell is now vulnerable without cell to external environment and ultimately dies.

The cell wall synthesis also inhibits when penicillin binds numerous proteins (PBP-penicillin binding proteins) on the bacterial cell membrane and inactivated its. This PBPs are important for bacterial cell wall synthesis and in the maintenance of bacterial morphology.

Penicillin also activated bacterial auto catalytic enzymes (autolysins) that kills bacteria by creating lesions.