Isolation and characterization of oligosaccharides from urine of patients with abnormal glycoconjugate metabolism

Use of chemical ionization in gas chromatographic/mass spectrometric screening of human urine for disaccharides containing inositol

Gas chromatography/mass spectrometry (GC/MS) in the positive chemical ionization (CI) mode was used to screen normal urine for inositol-containing disaccharides in the form of permethylated derivatives, after borodeuteride reduction of the reducing saccharides. Ammonia was the reactant gas. The results revealed the existence of deoxyhexosyl-inositol and hexosyl-inositol disaccharides, and of a new compound, N-acetylhexosaminyl-inositol disaccharide. Up to four isomers of deoxyhexosyl-inositol could be present in the same sample even though only one of them has so far been fully characterized in man. As regards the hexosyl-inositols, one to three isomers were present in the same sample and probably corresponded to the three isomers of galactosyl-inositol recently described in man. N-Acetylhexosaminyl-inositol (identified elsewhere by us as N-acetylgalactosaminyl-alpha (1-1)-myo-inositol) was seen in only a few samples. No relationship can be found between the excretion of all these inositol-containing disaccharides on the one hand, ABO(H) blood group and 'Secretor' status (Se or sese) of the donors on the other. The gas chromatographic CI mass spectrometric technique used here with various ammonia pressures can be applied to the screening of other biological fluids or tissues for inositol glycosides.

Urinary excretion of oligosaccharides induced by galactose given orally or intravenously

The effect of oral administration of galactose, lactose, and sucrose and intravenous injection of galactose on the urinary excretion of blood-group-active oligosaccharides has been studied. Galactose given either as the free sugar, a glycoside (lactose) or a constituent of normal diet was an absolute requirement for the formation and excretion of A-trisaccharide, B-trisaccharide and 2'-fucosylgalactose in blood group A, B and O(H) secretors, respectively. Great individual variation was seen in the amounts of galactose-dependent oligosaccharides excreted. Injection of galactose resulted in excretion of 3-59% of the amount of oligosaccharide formed after oral administration to the same individual. The mean ratio A-trisaccharide/B-trisaccharide was 2.7 in four blood-group-A1B secretors and 0.22 in three A2B secretors and can thus serve as a parameter for chemical differentiation between the two blood groups. The excretion of larger blood-group-active oligosaccharides, including the A-pentasaccharide, the B-pentasaccharide and lactodifucotetraose, that are normal components in urine from, respectively, starved A, B, and H secretors, was about the same after oral administration of galactose or lactose. The B-trisaccharide was the only oligosaccharide detected in plasma after oral galactose administration to a blood-group-B secretor individual. The concentration was 0.38 mg/l of plasma.