Abstract
Microorganisms are reported to use siderophores as iron carriers in their high-affinity type iron-uptake systems. Since siderophores form rather stable complexes with ferric iron, the release of iron from internalized complexes is probably accomplished through reduction to ferrous forms, being catalyzed by ferric reductases. In the present study, one of the ferric reductases from the soluble fraction of Vibrio anguillarum E6-5 was partially purified and characterized. This was an NADH-dependent ferric reductase with ability to reduce different iron complexes such as ferric citrate, ferric-EDTA, and ferric chloride. Effects of flavin derivatives, metal ions, dithiothreitol (DTT), and β-mercaptoethanol were also studied. In gel filtration chromatography, the enzyme showed an apparent molecular mass of 26 kDa. Upon native-PAGE analysis, the partially purified preparation gave a single band with ferric reductase activity.
