Sialo-oligosaccharides sialyl

In terms of preparative chemistry, the use of CMP- 3-Neu5Ac as a glycosyl donor and (cloned) a-2,3/6-sialyltransferases as biocatalysts have achieved a permanent position in the planning of synthetic routes for sialo-oligosaccharide chains see e.g. refs. [314,342, 345,351,472,473,535-544]. Especially in the field of the preparation of sialyl Le frag-... 

Neuraminidase Deficiency. A simple defect in lysosomal neuraminidase has only recently come to light (Lowden and O Brien, 1979 Kuriyama etal, 1979). Patients with this storage disease put out sialo-oligosaccharides in their urine. Fibroblasts from the patient of Kuriyama et al, (1979) showed an extreme deficiency in neuraminidase activity towards a2,3-sialyl lactose, a2,6-sialyl lactose and fetuin. Hence more than one enzyme might be involved. 

Using this new sialyl phosphate donor 45, more than 50 different sialosides have been synthesized by combining several strategies (Fig. 7) that allow stereoselective, one-pot multicomponent synthesis of a-sialo oligosaccharides. These sialosides were further used in the preparation of a glycan array for the quantitative and... 

Chemical analysis throws a little light on the problem. Oligosaccharides are known from several sources in which the bi-antennary structure of asialo-transferrin occurs as the inner part of sialo-glycopeptide sequences. In some the structure has two terminal a2,3 sialyl groups (Strecker etal, 1977 Burke and Keegstra, 1979), while in others both are in the a2,6 configuration. Cases of simultaneous presence of both types of link are also known (Strecker etal, 1977). 

Figure 17.1 Examples of important sialylated oligosaccharide structures illustrating the common linkage types found for natural sialo-conjugates-...

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