A NEW PROCEDURE FOR THE REDUCTION OF URONIC-ACID CONTAINING POLYSACCHARIDES

The presence of uronic acid residues in polysaccharide induces a diffi cult quantitative determination of monosaccharides. Reduction of uroni c acid into corresponding hexose allows a complete monosaccharide libe ration by acidic treatment. However, reduction methods previously desc ribed have not permitted a quantitative reaction. This paper describes a new quantitative reduction procedure for the uronic acid containing different polysaccharides. Uronic acid reduction is performed by meth ylesterification in dimethylsulfoxide/ methanol with diazomethane foll owed by reduction in imidazol buffer with potassium borohydride. Moreo ver, the technique allows a quantitative reaction of low quantities of polymer without polymer degradation.