resumo
The hydroxyl radicals are widely implicated in oxidation of carbohydrates during biological and industrial processes being responsible for their structural modifications and causing functional damage. The identification of intermediate oxidation products is hampered by a lack of reliable sensible methods for their detection. In this study, the oxidation of two models of galactomannans (Man(3) and GalMan(2)) has been studied in reaction with hydroxyl radical generated by Fenton reaction. The oxidation patterns were assessed using preparative ligand-exchange/size-exclusion chromatography (LEX/SEC) coupled with tandem electrospray mass spectrometry (ESI-MS/MS). This allowed the identification of derived oligosaccharides (OS) containing hexuronic, hexonic, pentonic and erythronic acid residues and neutral OS bearing hydroperoxy, hydrated carbonyl moieties and residues from pyranosyl ring cleavage. The depolymerization products have been also detected upon oxidation of oligomers. This study allowed developing a simple, effective 'fingerprinting' protocol for detecting the damage done to mannans by oxidative radicals. (C) 2011 Elsevier Ltd. All rights reserved.
palavras-chave
AQUEOUS-SOLUTION; STRUCTURAL-CHARACTERIZATION; RADIATION-CHEMISTRY; PEROXYL RADICALS; HYALURONIC-ACID; IDENTIFICATION; DEGRADATION; POLYSACCHARIDES; PRODUCTS; SCISSION
categoria
Biochemistry & Molecular Biology; Chemistry
autores
Tudella, J; Nunes, FM; Paradela, R; Evtuguin, DV; Domingues, P; Amado, F; Coimbra, MA; Barros, AIRNA; Domingues, MRM
nossos autores
Dmitry Evtyugin
Professor Associado com Agregaçãoagradecimentos
The authors thank the financial support provided to project PTDC/QUI-QUI/100044/2008, QOPNA -Research Unit 62/94 (project PEst-C/QUI/U10062/2011), Research Unit in Vila Real (POCTI-SFA-3-616) and RNEM by the Foundation for Science and Technology (FCT) and COMPETE.