Galactose paper chromatography

Acid hydrolysis of the basic hexasaccharide yielded the disaccharide 31. Its mobility in paper chromatography lay between those of the corresponding (1 — 3)-linked (from S10A) and /3-(l — 6)-linked (from S29) isomers, which is why it was assumed to be (1 — 4)-linked. The (1 — 2)-linked isomer was excluded, as the D-galactose residue that is part of 31 carries a D-galactopyranosyl group linked to 0-2 in the original polysaccharide, as will be discussed. 

A better method has been described by Schwarz (S6). Washed red blood cells are lysed, precipitated with trichloroacetic acid below 0°C and the supernatant quickly neutralized. Speed and low temperatures are necessary to prevent hydrolysis of galactose-l-phosphate which is very sensitive to acid. Barium acetate and ethanol are added, and the precipitated barium salt of galactose-l-phosphate washed with 80% ethanol. The barium salt is then hydrolyzed by heating with dilute hydrochloric acid, acid and salts removed with mixed ion-exchange resins, and the galactose estimated by paper chromatography as described above. It is probably better to avoid the Amberlite MB-1 resin used by Schwarz and, instead, to use a weak base resin mixture, such as Amberlite MB-4. Recovery of added galactose-l-phosphate should be determined simultaneously. 

To identify the components of the hydrolysis mixture, it is essential that they be isolated in the crystalline state or as crystalline derivatives. Some sugars, for instance galactose, which occurs in both d- and L-forms, cannot otherwise be properly identified, and unexpected sugars can be confused with commoner sugars if they are identified by paper chromatography only. 

Only trace amounts of monosaccharides have so far been detected in soils. The reducing sugars in cold-water extracts of Norwegian soils amounted to less than 1% of the total soil organic matter (2% for peats). Glucose, galactose, xylose, and rhamnose have been identified by paper chromatography in sodium hydroxide extracts of various Scottish soils. 

Occurrence and preparation. The major heptose of the LPS of Vibrio cholera Inaba 569B was proved to be D-glycero-h-manno-heptose (47), by isolating the sugar through repeated purification on paper chromatography, and was confirmed by comparison with an authentic sample (synthesized via condensation of nitromethane with D-galactose).246... 

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