1H-n.m.r. analysis of glycolipids possessing mono- and multi-meric X and Y haptens: characterization of two novel extended Y structures from human adenocarcinoma.

Analysis of glycolipids having repeating core-structures of type 2 chains ([Gal beta 1----4GlcNAc beta 1----3]nGal beta 1----4Glc beta 1----1Cer) by 1- and 2-dimensional high resolution 1H-n.m.r. spectroscopy shows that fucosylation alpha 1----3 to GlcNAc with or without fucosylation alpha 1----2 to Gal produces predictable chemical shifts of anomeric protons and systematic, glycosylation-induced shift changes. These effects were analyzed for a series of glycolipids of known structure bearing mono- and multimeric X [Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----3] and Y [Fuc alpha 1----2Gal beta 1----4-(Fuc alpha 1----3)GlcNAc beta 1----3] determinants, and were subsequently used to elucidate the primary saccharide structure of two novel glycolipids isolated from human liver adenocarcinoma. They are proposed to be Y determinants carried on a norhexaosylceramide core, with the following structures: (Formula: see text).