title: Oxidation of cell wall polysaccharides by hydrogen peroxide: a potential mechanism for cell wall breakdown in plants.
abstract: Incubation of cellulose, sodium carboxylcellulose, pectin, polygalacturonic acid, xylan and arabinogalactan with hydrogen peroxide (0.1-10 mM) resulted in rapid breakdown of the polysaccharides when measured by a reduction of solution viscosity or an increase in reducing groups. When the reaction mixtures were precipitated with ethanol or fractionated on G-25-300 Sephadex, low molecular weight reducing groups increased with incubation time indicating that polymer cleavage was occurring and not simply polymer modification. Oxidation was most rapid at pH 6.5 or 7.5, although secondary optima between pH 3.5 and 5.5 were also observed, depending on the polysaccharide. Purified cell walls isolated from various organs of tomato, cucumber and soybean were similarly degraded and the ethanol-soluble reaction products were partially characterized. The data support the hypothesis that hydrogen peroxide generated by peroxidase from NADH may play a role during cell wall breakdown in plants.
mesh_terms: D002384:Catalysis; D002473:Cell Wall; D055598:Chemical Phenomena; D002621:Chemistry; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D018521:Plant Physiological Phenomena; D011134:Polysaccharides
chemical_list: D011134:Polysaccharides; D006861:Hydrogen Peroxide