Oligosaccharides degradative technique

PDMS of native LOS-I showed a [M + Na]+ ion at m/z 1823, confirming the presence of one of each of C15, C15 OH, and C25 fatty acids per molecule of LOS and fragment ions of mlz 245.6, 477.3, 706.9, 993.9, and 1282.4 supported the evidence for the structure of LOS-I, showing that the fatty acids are present on the terminal 2-O-methyl-glucose of the trehalose unit. Similarly, for the LOS from the unknown Mycobacterium, the location of the acyl functions was confirmed by using PDMS. Thus, a combination of alkylation and degradation techniques and PDMS may be used simultaneously to establish the nature and position of the acyl functions on the lipo-oligosaccharides. 

This degradative technique is also applicable to higher oligosaccharides. For example, a trisaccharide was characterized as 0-p-D-glucopyranosyl-(l 4)-(9-p-D-glucopyranosyl-(l 3)-o-glucose (95) by the following series of reactions ... 

D-glucosyl-L-arabinose disaccharide by oxidative degradation with nin-hydrin, and this technique may be of value with other amino sugar oligosaccharides. The studies of Rabat and others suggest that, in the... 

The identification of oligosaccharide products, which relies on chemical methods such as periodate and lead tetraacetate oxidation, partial acid hydrolysis before and after reduction, electrophoretic mobility in borate and molybdate buffers and chromatography, has been described by Bouveng and Lindberg (29). The alkaline degradation products of oligosaccharides are characteristic of the linkage present and a TLC technique for their separation and detection has recently been described (16). 

Although this technique has been most widely used for examination of oligosaccharides of the type obtained from starch and glycogen, there is no reason why it should not be employed for examining the degradation products (enzymic or nonenzymic) of other types of polysaccharides. For illustrations of the results of the technique, see Refs. 73 and 74. 

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