title: Mechanisms of depolymerization and activation of a polysialic acid and its tetramer by hydrogen peroxide.
abstract: Naturally occurring polysialic acid (PSA), appropriately functionalized, has been widely used in different biological products. The present paper describes an original approach which enables to both activate and depolymerize the PSA, by reacting with hydrogen peroxide. In order to understand the mechanisms, we investigate the course of H2O2 reactions with the native PSA and with a simpler model, the tetrasialic acid (4SA). Three recurrent reactions were observed. First, we detected a very fast and irreversible decarbonylation at the reducing end of the polysaccharide. Then, the hydroxyl radicals (generated via the Fenton reaction) were responsible for the depolymerization of glycosidic linkages by substitution reactions. Finally, the oxidation of hydroxyl groups led to the formation of carbonyl groups and the carbohydrate's activation.
authors.affiliation: Université de Lyon, Université Lyon 1, Faculté de Pharmacie - ISPB, EA 4446 Biomolécules Cancer et Chimiorésistances, SFR Santé Lyon-Est CNRS UMS3453 - INSERM US7, 8 avenue Rockefeller, F-69373, Lyon Cedex 8, France. Electronic address: chrisneyra@gmail.com.
authors.forename: C
authors.initials: C
authors.lastname: Neyra
authors.affiliation: Université de Lyon, Université Lyon 1, Faculté de Pharmacie - ISPB, EA 4446 Biomolécules Cancer et Chimiorésistances, SFR Santé Lyon-Est CNRS UMS3453 - INSERM US7, 8 avenue Rockefeller, F-69373, Lyon Cedex 8, France. Electronic address: joseph.paladino01@gmail.com.
authors.forename: J
authors.initials: J
authors.lastname: Paladino
authors.affiliation: Université de Lyon, Université Lyon 1, Faculté de Pharmacie - ISPB, EA 4446 Biomolécules Cancer et Chimiorésistances, SFR Santé Lyon-Est CNRS UMS3453 - INSERM US7, 8 avenue Rockefeller, F-69373, Lyon Cedex 8, France.
authors.forename: M
authors.initials: M
authors.lastname: Le Borgne
mesh_terms: D006861:Hydrogen Peroxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D058105:Polymerization; D012794:Sialic Acids / Q000737:chemistry*
chemical_list: D012794:Sialic Acids; C021319:polysialic acid; D006861:Hydrogen Peroxide
keywords: Activation; Depolymerization; Hydrogen peroxide; Polysialic acid; Tetrasialic acid