B blood group substance

Figure 52-6. Diagrammatic representation of the structures of the H, A,and B blood group substances. R represents a long complex oligosaccharide chain, joined either to ceramide where the substances are glycosphingolipids, or to the polypeptide backbone of a protein via a serine or threonine residue where the substances are glycoproteins. Note that the blood group substances are biantenna ry ie, they have two arms, formed at a branch point (not indicated) between the GIcNAc—R, and only one arm of the branch is shown. Thus, the H, A,and B substances each contain two of their respective short oligosaccharide chains shown above. The AB substance contains one type A chain and one type B chain.

XLVIII. Activity of Fucose-Containing Oligosaccharides Isolated from Human Urine and from Human Ovarian Cyst A and B Blood Group Substances, /. Immunol. (1971) 106,1572 ... 

Figure 16.15 Biosynthesis of O-linked oligosaccharide units on glycoproteins of the O, A, and B blood group substances. 

The ABO substances have been isolated and their structures determined simphfied versions, showing only their nonreducing ends, are presented in Figure 52—6. It is important to first appreciate the structure of the H substance, since it is the precursor of both the A and B substances and is the blood group substance found in persons of type O. H substance itself is formed by the action of a fiicosyltransferase, which catalyzes the addition of the terminal fiicose in al —> 2 linkage onto the terminal Gal residue of its precursor ... 

The ABO blood group substances in the red cell membrane are complex glycosphingohpids the immunodominant sugar of A substance is A -acetyl-galactosamine, whereas that of the B substance is galactose. 

Smith, H.V., Kusel, J.R. and Girdwood, R.W.A. (1983) The production of human A and B blood group like substances by in vitro maintained second stage Toxocara canis larvae their presence on the outer larval surfaces and in their excretions/secretions. Clinical and Experimental Immunology 54, 625-633. 

The saliva of secretors has been used as a source of blood group substances in several investigations. Landsteiner obtained very active material from horse saliva and was able to show that it contained D-galac-tose and a hexosamine. More recently the same author compared the blood group substances from the saliva of individuals of groups A, B and 0 and found that there was very little difference in their properties (see Table III). 

Although no complete investigations of the structure of the blood group substances have yet been reported, it is evident from the information available that all the material so far studied is predominantly carbohydrate in nature, and, as can be seen from Table III, preparations from widely different sources have many properties in common, for example, elementary analysis, specific rotation and the like. It is of interest to note that almost all the substances obtained from nonhuman sources display blood group A or blood group O activity, while human material is the most convenient source of the blood group B substance. The majority of the work carried out so far has dealt with blood group A substances. 

U. E. Udodong, C. S. Rao, and B. Fraser-Reid, n-Pentenyl glycosides in the efficient assembly of the blood group substance B tetrasaccharide, Tetrahedron 48 4713 (1992). 

Isolation and Characterization of a Substance from Human Ovarian Cyst Fluid of a Blood Group Substance Lacking A, B, H, Lea, and Leb Specificity, J. Immunol (1969) 102,821. 

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