Oligosaccharides groups

Glycohpids (5,14) are primarily glycosphingoHpids, molecules that have oligosaccharide groups attached to ceramide [104404-17-3]. They are present, at least in small amounts, in the membranes of most, if not all, tissues. They too, like cell-membrane glycoproteins, are recognition deterrninants. 

FIGURE 7.20 Some antibiotics are oligosaccharides or contain oligosaccharide groups. 

Figure 8-5 The fluid mosaic model of Singer and Nicolson.61 Some integral membrane proteins, which are shown as irregular solids, are dissolved in the bilayer. Transmembrane proteins protrude from both sides. One of these is pictured as a seven-helix protein, a common type of receptor for hormones and for light absorption by visual pigments. Other proteins adhere to either the outer or the inner surface. Many membrane proteins carry complex oligosaccharide groups which protrude from the outer surface (Chapter 4). A few of these are indicated here as chains of sugar rings.

Oligosaccharide units, discussed in the previous section, are relatively small. The molecular weight of the transferrin oligosaccharide group, for example, is... 

In some glycoproteins, the oligosaccharide takes an active part in the biological activity of Ihe protein, while in many other cases, there appears to be absolutely no function of the oligosaccharide group (Varki, 1993). 

The endoglycosidase, ceramide glycanase, is used to transfer an oligosaccharide group from a water-soluble polymer to ceramide. This enzymatic tool provides an efficient new method for polymer-supported synthesis of glycosphingolipids (119). 

Gangliosides are glycolipids that possess oligosaccharide groups, including one or more molecules of N-acetylneuraminic acid (sialic acid). First isolated from membranes of nerve tissue, gangliosides are found in most tissues of the body. 

Polymers bearing pendant oligosaccharide groups have also been investigated as possible sequestrants for C. difficile toxins (72,73). This approach is based on the principle that toxin A has shown a lectin-like activity, which allows it to bind to an oligosaccharide receptor on epithelial cells. Fmthermore, toxin B has... 

More than 20 blood group systems are known having 160 distinct antigenic oligosaccharide groupings. They are present on other cells as well as red blood corpuscles and are found attached to mucous secretions including saliva. 

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