TABLE 3.
Localization of the iron(III) reductase in the outer membrane fraction of G. sulfurreducens
| Fraction | Protein (mg) | KDO
content
|
Iron(III) reductase
activitya with:
|
||||
|---|---|---|---|---|---|---|---|
| Total (mg) | Specific (ng/mg of protein) | NADH
|
Horse heart cytochrome
c
|
||||
| Sp act (mU/mg of protein) | Total activity (mU) | Sp act (mU/mg of protein) | Total activity (mU) | ||||
| Low-density band | 0.85 ± 0.04 | 2.60 ± 0.04 | 77 ± 5 | 112 ± 12 | 95.2 ± 10 | 122 ± 15 | 103 ± 12 |
| High-density band | 1.02 ± 0.06 | 0.20 ± 0.02 | 2.2 ± 0.2 | 25 ± 4 | 25.5 ± 4 | 33 ± 3 | 33.6 ± 3 |
a
Reactions were performed in 50 mM HEPES buffer (pH 7) containing 0.3 mM Fe(III)-NTA, 0.5 mM ferrozine, and either 1 mM NADH or 4 μM horse heart cytochrome c. An activity of 1 mU corresponds to 1 nmol of Fe(II) formed per min.