Identification and quantification of radical reaction intermediates by electron spin resonance spectrometry of laccase-catalyzed oxidation of wood fibers from beech ( Fagus sylvatica )
| Autor: | Leif H. Skibsted, Per Ole Olesen, Claus Felby, Bo R. Nielsen |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Laccase
biology Superoxide Cytochrome c Radical fungi technology industry and agriculture General Medicine Reaction intermediate Photochemistry complex mixtures Applied Microbiology and Biotechnology chemistry.chemical_compound chemistry biology.protein Organic chemistry Lignin Phenol Hydroxyl radical Biotechnology |
| Zdroj: | Applied Microbiology and Biotechnology. 48:459-464 |
| ISSN: | 1432-0614 0175-7598 |
| DOI: | 10.1007/s002530051080 |
| Popis: | During laccase-catalyzed oxidation of beech wood fibers in an aqueous suspension, phenoxy radicals were detected in steady-state concentrations by electron-spin resonance (ESR) spectrometry of the suspension liquid, suggesting that colloidal lignin functions as a mediator between laccase and the fiber lignin matrix. Phenoxy radicals were observed directly, whereas ESR spin-trapping techniques gave no evidence for reduced oxygen species, such as the superoxide or hydroxyl radical. A reaction mechanism involving parallel direct oxidation of the lignin on fiber surfaces and a phenol/phenoxy cyclic mediator process in the suspension liquid could accordingly describe laccase-catalyzed oxidation of beech wood fibers. Cytochrome c assays for detection of superoxide in systems involving lignin oxidized by oxidoreductases should be used with caution, as cytochrome c may be reduced by species other than superoxide. |
| Databáze: | OpenAIRE |
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