on the basis of o-deacetylation , selective cleavage with anhydrous fluoride , chemical transformation of the oligosaccharides obtained ( hydrolysis or reductive deamination of the acetamidino group into acetamido or ethylamino group , respectively ) and analysis by 13c nmr spectroscopy , it was concluded that the polysaccharide is built up mainly by trisaccharide repeating units of types a and b in the ratio approximately 2:1 : ( formula : see text ) .
C0028959
oligosaccharides
C0032594
polysaccharide