Hydrolysis neutral methylated polysaccharides

B. Partial Acid Hydrolysis of Neutral Methylated Polysaccharides... 

B. PARTIAL ACID HYDROLYSIS OF NEUTRAL METHYLATED POLYSACCHARIDES... 

Formolysis and acetolysis are not common methods for cleavage of glycosidic linkages. They do have some unique applications, however. For instance, methylated polysaccharides are not generally soluble in hot water, and consequently, hydrolysis is best preceded by formolysis under these circumstances. For example, 5 mg of methylated polysaccharide is dissolved in 3 mL of 90% formic acid, and the solution is kept for 2 h at 100°. The formic acid is removed by evaporation at 40°. The residue is dissolved in 1 mL of 250 mM sulfuric acid and the solution is heated for 12 h at 100°, cooled, the acid neutralized with barium carbonate, the... 

Mixtures containing nearly all possible partially methylated alditol acetates have been prepared as standards for the methylation analysis of cell-wall polysaccharides. Incomplete Hakamori methylation (1.e. limiting amounts of potassium dimsyl) of neutral monosaccharides with purification of the derivatives on a C g reversed-phase column was followed by standard hydrolysis, reduction, and acetylation. Relative capillary g.c. retention data was... 

An established microchemical procedure for determining the DP of neutral oligo-and poly-saccharides has been used in studies on D-glucans. The site of attachment of the rest of the chain to the reducing-end residue of an oligosaccharide or a polysaccharide (e.g. amylose or laminarin) can be established using the sequence of reduction, methylation (or ethylation), acidic hydrolysis, and g.l.c.-m.s. of the resulting alkylated alditol. ... 

---