title: A second phenazine methosulphate-linked formate dehydrogenase isoenzyme in Escherichia coli.
abstract: A biochemical and immunological study has revealed a new formate dehydrogenase isoenzyme in Escherichia coli. The enzyme is an isoenzyme of the respiratory formate dehydrogenase (FDH-N) which forms part of the formate to nitrate respiratory pathway found in the organisms when it is grown anaerobically in the presence of nitrate. The new enzyme, termed FDH-Z, cross reacts with antibodies raised to FDH-N and possesses a similar polypeptide composition to FDH-N. FDH-Z catalyses the phenazine methosulphate-linked formate dehydrogenase activity present in the aerobically-grown bacterium. FDH-Z and FDH-N exhibit distinct regulation. Like formate dehydrogenase N, formate dehydrogenase Z is a membrane-bound molybdoenzyme. With nitrate reductase it can catalyse electron transfer between formate and nitrate. Quinones are required for the physiological electron transfer to nitrate. It seems likely that like FDH-N, FDH-Z functions physiologically as a formate: quinone oxidoreductase.
authors.affiliation: Laboratoire de Chimie Bacterienne, CNRS, Marseille, France.
authors.forename: J
authors.initials: J
authors.lastname: Pommier
authors.forename: M A
authors.initials: MA
authors.lastname: Mandrand
authors.forename: S E
authors.initials: SE
authors.lastname: Holt
authors.forename: D H
authors.initials: DH
authors.lastname: Boxer
authors.forename: G
authors.initials: G
authors.lastname: Giordano
mesh_terms: D004579:Electron Transport / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology* / Q000276:immunology; D005560:Formate Dehydrogenases / Q000032:analysis* / Q000276:immunology; D007527:Isoenzymes / Q000032:analysis* / Q000276:immunology; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000032:analysis; D011809:Quinones / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D011809:Quinones; D005560:Formate Dehydrogenases; D009565:Nitrate Reductases; D050901:Nitrate Reductase