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A second phenazine methosulphate-linked formate dehydrogenase isoenzyme in Escherichia coli

1992; Elsevier BV; Volume: 1107; Issue: 2 Linguagem: Inglês

10.1016/0005-2736(92)90417-k

1879-2642

Janine Pommier, Marie André Mandrand, Susan E. Holt, David H. Boxer, Gérard Giordano,

Metalloenzymes and iron-sulfur proteins

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.