Penicillin G Sodium Salt [Benzyl Penicillin Sodium Salt], 5 Grams

Penicillin G sodium is the sodium salt form of penicillin G, which is a narrow-spectrum beta-lactam antibiotic. It is one of the earliest and most widely used antibiotics, belonging to the penicillin class of antibiotics. 

Penicillin G sodium interferes with bacterial cell wall synthesis. It inhibits the enzyme transpeptidase, which is involved in the cross-linking of peptidoglycan chains in the bacterial cell wall. This disruption weakens the cell wall structure, leading to cell lysis and death.

Also, Penicillin G is effective against a wide range of Gram-positive bacteria, including Streptococcus, Staphylococcus, and some anaerobic bacteria. It is less effective against Gram-negative bacteria.

Often used as a selective agent in culture media to isolate bacteria that are sensitive to this antibiotic. Its inclusion in culture medium allows for the specific growth of bacteria lacking resistance to penicillin G.