Differential binding properties of Ga1NAc and/or Ga1 specific lectins.

Grouping of lectin binding properties, based on determinant structure rather than monosaccharide inhibition pattern, should facilitate the selection of lectins as structural probes for glycans as well as for the interpretation of the distribution and the properties of the carbohydrate chains on the cell surface. Based on the binding specificities studied with glycan by precipitin-inhibition, competitive-binding and hemagglutinin-inhibition assays, twenty Ga1 and/or Ga1NAc specific lectins have been divided into six classes according to their specificity for the disaccharide as all or part of the determinants and Ga1NAc alpha 1----Ser(Thr) of the peptide chain. The differential affinities of these lectins were characterized by quantitative precipitin assay. Abbreviation of the following six lectin determinants can also be used to classify these lectins. (1) F determinant (GalNAc alpha 1----3GalNAc, Forssman specific disaccharide). (2) A (Af) determinant (GalNAc alpha 1----3Gal, Human blood group A specific disaccharide; Af, fucosylated A, (GalNAc alpha 1----3 [LFuc alpha 1----2]Gal). (3) Tn determinant (GalNAc alpha 1----0 to Ser (Thr) of the protein core, Tn antigen). (4) T determinant (T antigen, Gal beta 1----3GalNAc alpha 1----0 to Ser (Thr) of the protein core, the mucin type sugar sequence on the human erythrocyte membrane or Gal beta 1----3GalNAc beta 1---- at the nonreducing end of ganglioside). (5) I and II determinants (human blood group type I and II carbohydrate sequences). Most of the lectins reactive to Gal beta 1----4GlcNAc (II) are also reactive to Gal beta 1----3GlcNAc (I). Lectin I (II) determinants (i.e. Gal beta 1----3 (4) GlcNAc residues) can be found at the nonreducing end of the carbohydrate chains derived from either N-glycosidic or O-glycosidic linkages. (6) B determinant (Gal alpha 1----3Gal, Human blood group B specific disaccharide). Their carbohydrate specificities are classified as following: (Table see text). The differential binding properties of lectins can be defined from comparisons of their carbohydrate specificities listed above.