Skip to main content

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.