Species: Gottschalkia acidurici
Subunit composition of NAD-dependent formate dehydrogenase = [NAD-dependent formate dehydrogenase subunit]
NAD-dependent formate dehydrogenase from Gottschalkia acidurici catalyzes a reversible reaction. While it catalyzes the oxidation of formate to CO2 as shown in the pathway purine nucleobases degradation II (anaerobic), it also catalyzes the reduction of the later to formate, which is then converted to acetate [Thauer73].
The enzyme has been partially purified and found to be a large enzyme complex (molecular weight of at least 200 kDa) that is very sensitive to oxygen and light [Kearny72]. The enzyme contains a L-selenocysteine [Heider93].
Crude preparations of the enzyme could be coupled to NAD reduction during formate oxidation through ferredoxin [Kearny72, Thauer73]. When the artificial electron acceptor methyl viologen was used instead of NAD, ferredoxin was not required [Kearny72]. Cyanide inhibited the enzyme 90%.
Interestingly, the enzyme from the related organism Clostridium cylindrosporum, while having a similar requirement for selenite, requires molybdate rather than tungstate, which has an antagonistic effect on it.
Molecular Weight of Multimer: 200 kD (experimental) [Kearny72]
Enzymatic reaction of: NAD-dependent formate dehydrogenase
EC Number: 18.104.22.168formate + NAD+ ⇄ CO2 + NADH
The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction of enzyme catalysis.
This reaction is reversible.Se0 [Wagner77] Inhibitors (Other): hydrogen cyanide [Kearny72], EDTA [Kearny72], oxygen [Kearny72], hν [Kearny72]Kinetic Parameters:
pH(opt): 7.8-8.2 [Kearny72]
Wagner77: Wagner R, Andreesen JR (1977). "Differentiation between Clostridium acidiurici and Clostridium cylindrosporum on the basis of specific metal requirements for formate dehydrogenase formation." Arch Microbiol 114(3);219-24. PMID: 911212
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