The process of halorespiration, or dehalorespiration, uses reductive dehalogenation to produce energy that can be used by the respiring microorganism to carry out its growth and metabolism.[6] Halogenated organic compounds are used as the terminal electron acceptor, which results in their dehalogenation.[6] Reductive dehalogenation is the process by which this occurs.[6] It involves the reduction of halogenated compounds by removing the halogen substituents, while simultaneously adding electrons to the compound.[7] Hydrogenolysis and vicinal reduction are the two known processes of this mechanism that have been identified.[7] In both processes, the removed halogen substituents are released as anions.[7] Reductive dehalogenation is catalyzed by reductive dehalogenases, which are membrane-associated enzymes.[6][8][4] A number of not only membrane-associated but also cytoplasmic hydrogenases, in some cases as part of the protein complexes, are predicted to play roles in the dehalorespiration process.[9] Most of these enzymes contain iron-sulfur (Fe-S) clusters, and a corrinoid cofactor at their active sites.[6] Although the exact mechanism is unknown, research suggests that these two components of the enzyme may be involved in the reduction.[6]