Glufosinate (also known as phosphinothricin and often sold as an ammonium salt) is a broad-spectrum systemic herbicide with the chemical formula C5H15N2O4P. It irreversibly inhibits glutamine synthetase, an enzyme necessary for the production of glutamine and for ammonia detoxification. Application of glufosinate to plants leads to reduced glutamine and elevated ammonia levels in tissues, halting photosynthesis, resulting in plant death.