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Table 1 Hydrogen-oxidizing enzyme activity of the feoB::Tn5 mutant PM06 grown in minimal medium with different iron sources

From: Iron restriction induces preferential down-regulation of H2-consuming over H2-evolving reactions during fermentative growth of Escherichia coli

Strain and iron supplementa Hydrogenase specific activityb
(μmol H2 oxidized min-1 mg protein-1)
  MC4100 PM06 (feoB::Tn5)
no iron addition 2.02 ± 0.64 0.49 ± 0.19
7.5 μM iron chloride (FeCl3) 3.63 ± 0.73 2.49 ± 0.64
15.3 μM hemin 1.72 ± 0.92 0.25 ± 0.18
10 μM potassium ferrocyanide (K4[Fe(CN)6]) (Fe2+) 1.34 ± 1.30 0.38 ± 0.33
10 μM potassium ferricyanide (K3[Fe(CN)6]) (Fe3+) 1.80 ± 2.82 0.93 ± 0.85
10 μM ferric ammonium sulfate (Fe(NH4)(SO4)2) 3.33 ± 2.53 2.02 ± 2.11
50 μM iron citrate (C6H5FeO7) 2.20 ± 0.70 3.47 ± 1.17
300 μM 2,2'-dipyridyl < 0.01 < 0.01
300 μM 2,2'-dipyridyl and 200 μM FeCl3 0.04 ± 0.07 < 0.01
300 μM 2,2'-dipyridyl and 200 μM iron citrate 1.59 ± 1.16 0.04 ± 0.06
  1. a Cells were cultivated in M9 minimal medium including 0.8% (w/v) glucose. Iron sources were added at the given final concentrations.
  2. b The activities were determined for triplicate experiments.