Depolymerization, complex acidic polysaccharides

Magnesium compounds retard cellulose depolymerization by deactivating the transition metal catalysts. In alkaline media where hydroxy-acids or products of polysaccharide degradation are present, magnesium forms stable complexes with transition metals. The formation of iron-magnesium complexes in particular is supported by interactions approximating the coordination number of iron (6) and one half the coordination number (3). 

Any systematic study of cell walls requires an a-D-galacturonanase to release pectic and other matrix components. Molecular structural studies have so far progressed that elaborate models showing the various polymeric constituents in juxtaposition have been generated. After enzymatic elimination of starch and protein, hydrolysis of the residual polysaccharide and estimation of the uronic acids and monosaccharides released furnish considerable information on the composition of agricultural samples. Partial depolymerization affords the complex, well-studied rhamnogalacturonans I and II (RG-I and RG-II). 

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