Parameters controlling the kinetics of ferric and ferrous hemeproteins reduction by hydrated electrons.
Biochim Biophys Acta
; 994(1): 47-51, 1989 Jan 19.
Article
em En
| MEDLINE
| ID: mdl-2909254
ABSTRACT
To clarify the processes of hemeproteins reduction, three classes of these proteins (ferric, ferrous and desFe) were reduced by hydrated electrons generated by pulse radiolysis. Spectral and kinetic investigations were made on alpha hemoglobin chain and myoglobin. Human alpha chain has been chosen to avoid all ferric contaminations and horse ferric myoglobin to eliminate all ferrous protein fractions. We have successively studied the influences of the iron presence, its oxidation state (II and III), the protein charge and the iron-ligand nature (H2O, OH-, N3- and CN-). For alpha human hemoglobin chain without metallic ion or with ferrous iron, the reduction rates are the same 1.1 +/- 0.2.10(10) M-1.s-1. In the case of horse ferric myoglobin, the reduction rates depend principally on the protein charge (from pH 6.3 to pH 9.5, the reduction rate of Mb(FeIII)N3- decreases from 2.5 +/- 0.5.10(10) M-1.s-1 to 1.2 +/- 0.2.10(10) M-1.s-1) and are also modulated by the equilibrium constant of the hemeprotein-ligand association (1.2 +/- 0.2.10(10) M-1.s-1 for Mb(FeIII)N3- and 0.8 +/- 0.2.10(10) M-1.s-1 for Mb(FeIII)CN-, at pH 9.8).
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Compostos Férricos
/
Compostos Ferrosos
/
Elétrons
/
Hemeproteínas
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1989
Tipo de documento:
Article
País de afiliação:
França