This prokaryotic enzyme catalyses the reversible reduction of CO2 to CO. The electrons are transferred to redox proteins such as ferredoxin. In purple sulfur bacteria and methanogenic archaea it catalyses the oxidation of CO to CO2, which is incorporated by the Calvin-Benson-Basham cycle or released, respectively. In acetogenic and sulfate-reducing microbes it catalyses the reduction of CO2 to CO, which is incorporated into acetyl CoA by EC 220.127.116.11, CO-methylating acetyl-CoA synthase, with which the enzyme forms a tight complex in those organisms. The enzyme contains five metal clusters per homodimeric enzyme: two nickel-iron-sulfur clusters called the C-Clusters, one [4Fe-4S] D-cluster; and two [4Fe-4S] B-clusters. In methanogenic archaea additional [4Fe-4S] clusters exist, presumably as part of the electron transfer chain. In purple sulfur bacteria the enzyme forms complexes with the Ni-Fe-S protein EC 18.104.22.168, ferredoxin hydrogenase, which catalyse the overall reaction: CO + H2O = CO2 + H2. cf. EC 22.214.171.124, aerobic carbon monoxide dehydrogenase.
EC 126.96.36.199 created 2003 (EC 188.8.131.52 created 1982, modified 1990, modified 2003, incorporated 2015), modified 2016