Wheat Germ Agglutinin: A Review of Recent Results
Résumé
Many biological molecules contain sugars: glycolipids, lipopoly-saccharides, glycoproteins, polysaccharides, mucopolysaccharides, and proteoglycans. For a long time, the role of the sugar moiety of these compounds has remained unknown. Thirty years ago, it was shown (1) that the antigenic determinants of blood group substances were the oligosaccharide residues of cell surface glycoconjugates. That these substances are highly antigenic is proven by the strong reaction (and sometimes the lethal consequences) which sets in after transfusion of an incompatible blood. Even leaving aside the numerous enzymatic reactions involved in the metabolism of glycoconjugates, there remains a large number of biological phenomena in which sugar-protein interactions are implied. A tremendous amount of work has been devoted to this subject in the last decade. Anti-sugar myeloma antibodies have been characterized (2). Bacterial (3) and plant (4) toxins bind to membrane glycoconjugates before exerting their cytotoxicity. Sugar binding proteins, called lectins (5), have been identified in almost all living things, from viruses to mammals, and bacteria and fungi to plants (6–13). Lectins are proteins, (or glycoproteins), devoid of enzymatic activity, which selectively bind simple carbohydrates, polysaccharides, and/or the sugar moieties of glycoconjugates.