Illustration of a bacterial dehalogenase (PceA), an enzyme that catalyzes the removal of halogen atoms from organic compounds. This is a reductive dehalogenase from the organohalide-respiring bacterium (ORB) Sulfurospirillum multivorans. It uses a cobamide cofactor (orange) and iron-sulfur clusters to reduce the substrate, which in this case is trichloroethene (TCE). Research is being conducted into the use of dehalogenases in the process of bioremediation to destroy environmental organohalide pollutants which contaminate soil and water. Such pollution can be caused by the human use of pesticides and halogenated solvents.