title: Understanding of the mode of action of Fe(III)-EDDHA as iron chlorosis corrector based on its photochemical and redox behavior.
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.
authors.affiliation: Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain. margg@quim.ucm.es
authors.forename: Mar
authors.initials: M
authors.lastname: Gómez-Gallego
authors.forename: Daniel
authors.initials: D
authors.lastname: Pellico
authors.forename: Pedro
authors.initials: P
authors.lastname: Ramírez-López
authors.forename: María J
authors.initials: MJ
authors.lastname: Mancheño
authors.forename: Santiago
authors.initials: S
authors.lastname: Romano
authors.forename: María C
authors.initials: MC
authors.lastname: de la Torre
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Sierra