Light induced redox reactions involving mammalian ferritin as photocatalyst.
J Photochem Photobiol B
; 41(1-2): 83-9, 1997 Nov.
Article
em En
| MEDLINE
| ID: mdl-9440316
ABSTRACT
Under excitation by visible light the iron storage protein ferritin catalyses the reduction of cytochrome c and viologens as well as the oxidation of carboxylic acids, thiol compounds, and sulfite. The photochemically active element of ferritin is its mineral ferrihydrite semiconductor core. Band-gap excitation of these microcrystals leads to generation of electron-hole pairs that are sufficiently long-lived and reactive to engage in redox reactions with components of the medium. Photoreduction of cytochrome c and viologens occurs due to electron transfer from the conduction band of the iron oxide cluster through the protein shell surrounding the ferritin core. Laser photolysis coupled with time-resolved kinetics spectroscopy showed the electron transfer to propylviologen sulfonate to proceed in the microsecond time range. In the absence of electron acceptor at pH < 7, light excitation results in photodissolution of the iron oxide cluster with concomitant formation of Fe(II). These novel findings concerning the photocatalytic activity of ferritin with its inherent biological implications are discussed.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Viologênios
/
Grupo dos Citocromos c
/
Ferritinas
Limite:
Animals
Idioma:
En
Revista:
J Photochem Photobiol B
Assunto da revista:
BIOLOGIA
Ano de publicação:
1997
Tipo de documento:
Article