Benzylpenicillin of penicillin allergy. Use during pregnancy is generally safe. It is in the penicillin and β-lactam class of medications. Benzylpenicillin was discovered in 1929 by Alexander Fleming and came into commercial use in 1942. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$0.24–2.72 per day. In the United States a course of treatment costs $100–200. As an antibiotic, benzylpenicillin is noted to possess effectiveness mainly against Gram-positive organisms. Some Gram-negative organisms such as "Neisseria gonorrhoeae" and "Leptospira
Penicillin amidase Penicillin amidase Also called penicillin acylase. In enzymology, a penicillin amidase () is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are penicillin and HO, whereas its two products are carboxylate and 6-aminopenicillanate. This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is penicillin amidohydrolase. Other names in common use include penicillin acylase, benzylpenicillin acylase, novozym 217, semacylase, alpha-acylamino-beta-lactam acylhydrolase, and ampicillin acylase. This enzyme participates in penicillin and cephalosporin biosynthesis. As of late 2007,