Penicillin G Potassium

Penicillin is a broad-spectrum β-lactam antibiotic. It binds to penicillin binding proteins (PBP). PBP catalyzes the synthesis of peptidoglycan, which is an important component of the bacterial cell wall. PBP catalyzes a pentaglycine crosslink between the alanine and lysine residues providing additional strength to the cell wall. The integrity of the cell wall is severely compromised without a pentaglycine crosslink, which leads to cell lysis and death. Penicillin G shows MIC₉₀ values of 0.03, 1 and 4 µg/ml for penicillin-susceptible, -intermediate and -resistant strains of S. pneumoniae, respectively. Resistance to β-lactams is commonly due to cells containing plasmid encoded β-lactamases.