The respiratory molybdo-selenoprotein formate dehydrogenases of Escherichia coli have hydrogen: benzyl viologen oxidoreductase activity

Table 1 Activity of enriched enzyme fraction with different electron donors

Electron donor and acceptor^a	Specific Activity (mU mg protein^-1)^b
H₂ and benzyl viologen	14.8 ± 2.3
Benzyl viologen without an electron donor	< 0.20
Formate and benzyl viologen	1.24 ± 1.0
Formate and PMS/DCPIP	638.3 ± 69

^a The buffer used was 50 mM sodium phosphate pH 7.2; BV was used at a final concentration of 4 mM; formate was added to a final concentration of 18 mM; and PMS/DCPIP were added at final concentrations of 20 μM and 78 μM, respectively.
^b The mean and standard deviation (±) of at least three independent experiments are shown.

ISSN: 1471-2180