Penicillin is the first antibiotic isolated from the mold
Penicillium noctum, specifically it is known as penicillin G (other name: benzylpenicillin) and belongs to a class of similar antibiotics called penicillins. Nowadays penicillin G is produced by
Penicillium chrysogenum fermentation. Penicillin G has activity against Gram-positive bacteria, but less activity against Gram-negative bacteria. It acts as a competitive inhibitor of the enzyme transpeptidase, which is needed by bacteria to make their cell walls. Meanwhile, β-lactamases (also called penicillinases) are enzymes produced by bacteria that deactivate penicillin G by destroying the β-lactam ring via hydrolysis. In rare cases, an allergy to penicillin G can cause an anaphylactic reaction, which can be deadly. Currently, the enzymatic hydrolysis of penicillin G gives 6-aminopenicillanic acid (6-APA) [
A0800], which is a basic raw material for the industrial production of semisynthetic β-lactamase-resistant and broad spectrum penicillins such as amoxycillin [
A2099] and ampicillin [
A2092].