TABLE 1.
Electron donors tested for iron(III) reductase activitya
| Electron donor | Concn (mM) | Chemical reduction of Fe(III) | Iron(III) reductase activity (mU/mg of protein) |
|---|---|---|---|
| NADH | 1 | No | 35 |
| NADPH | 1 | No | 0 |
| Benzyl viologen | 0.5 | Yes | ND |
| Methyl viologen | 0.5 | Yes | ND |
| Phenosafranin | 0.5 | Yes | ND |
| Safranin T | 0.5 | Yes | ND |
| Neutral red | 0.5 | Yes | ND |
| Bromophenol blue | 0.5 | No | 0 |
| Horse heart cytochrome c | 0.004 | No | 30 |
a
Reactions were performed in 50 mM HEPES buffer (pH 7) containing 0.3 mM Fe(III)-NTA and 0.5 mM ferrozine. An activity of 1 mU corresponds to 1 nmol of Fe(II) formed per min. ND, not determined.