The heme domain of cellobiose oxidoreductase: a one-electron reducing system.
Biochim Biophys Acta
; 1604(1): 47-54, 2003 Apr 18.
Article
em En
| MEDLINE
| ID: mdl-12686420
ABSTRACT
Phanerochaete chrysosporium cellobiose oxidoreductase (CBOR) comprises two redox domains, one containing flavin adenine dinucleotide (FAD) and the other protoheme. It reduces both two-electron acceptors, including molecular oxygen, and one-electron acceptors, including transition metal complexes and cytochrome c. If the latter reacts with the flavin, the reduced heme b acts merely as a redox buffer, but if with the b heme, enzyme action involves a true electron transfer chain. Intact CBOR fully reduced with cellobiose, CBOR partially reduced by ascorbate, and isolated ascorbate-reduced heme domain, all transfer electrons at similar rates to cytochrome c. Reduction of cationic one-electron acceptors via the heme group supports an electron transfer chain model. Analogous reactions with natural one-electron acceptors can promote Fenton chemistry, which may explain evolutionary retention of the heme domain and the enzyme's unique character among secreted sugar dehydrogenases.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Desidrogenases de Carboidrato
/
Heme
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
2003
Tipo de documento:
Article