What is "pyocyanin"

Pyocyanin \Py`o*cy"a*nin\, n. [Gr. ? pus + ? dark blue.] (Physiol. Chem.) A blue coloring matter found in the pus from old sores, supposed to be formed through the agency of a species of bacterium ( Bacillus pyocyaneus).

n. (context biochemistry English) A greenish-blue pigment, produced by ''Pseudomonas aeruginosa'', that is an antibiotic and antifungal agent

n. a toxic blue crystalline antibiotic found in green pus

Pyocyanin (PCN) is one of the many toxins produced and secreted by the Gram negative bacterium Pseudomonas aeruginosa. Pyocyanin is a blue, secondary metabolite with the ability to oxidise and reduce other molecules and therefore can kill microbes competing against P. aeruginosa as well as mammalian cells of the lungs which P. aeruginosa has infected during cystic fibrosis. Since pyocyanin is a zwitterion at blood pH, it is easily able to cross the cell membrane. There are three different states in which pyocyanin can exist; oxidized, monovalently reduced or divalently reduced. Mitochondria play a huge role in the cycling of pyocyanin between its redox states. Due to its redox-active properties, pyocyanin generates reactive oxygen species.