Understanding of the Mode of Action of FeIII–EDDHA as Iron Chlorosis Corrector Based on Its Photochemical and Redox Behavior
✍ Scribed by Mar Gómez-Gallego; Daniel Pellico; Pedro Ramírez-López; María J. Mancheño; Santiago Romano; María C. de la Torre; Miguel A. Sierra
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 172 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
Abstract
The very low reduction potential of the chelate Fe^III^–EDDHA (EDDHA= ethylenediamine N,N′‐bis(2‐hydroxy)phenylacetic acid) makes it unreactive in photochemically or chemically induced electron transfer processes. The lack of reactivity of this complex toward light invalidates photodegradation as an alternative mechanism for environmental elimination. However, in spite of its low reduction potential, the biological reduction of Fe^III^–EDDHA is very effective. Based on electrochemical measurements, it is proposed that Fe^III^–EDDHA itself is not the substrate of the enzyme ferric chelate reductase. Likely, at the more acidic pH in the vicinity of the roots, the ferric chelate in a closed form (FeL^−^) could generate a vacant coordination site that leads to an open hexacoordinate species (FeHL) where the reduction of the metal by the enzyme takes place.