NCIt definition : A broad-spectrum, beta-lactam naturally occurring penicillin antibiotic with antibacterial
activity. Penicillin G binds to and inactivates the penicillin binding proteins (PBPs)
located inside the bacterial cell wall. Inactivation of PBPs interferes with the cross-linkage
of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This
interrupts bacterial cell wall synthesis and results in the weakening of the bacterial
cell wall and eventually causing cell lysis.;