Tissue specificity of glycosphingolipids as expressed in pancreas and small intestine of blood group A and B human individuals

Abstract

A chemical investigation has been done on blood group active glycosphingolipids of both small intestine and pancreas from two individuals, one blood group A and one blood group B. Total non-acid glycolipid fractions were prepared and the major blood group fucolipids present were purified and structurally characterized by mass spectrometry, proton NMR spectroscopy, and degradation methods. The glycolipid structures identified were a blood group Le b hexaglycosylceramide, a B-hexaglycosylceramide with a type 1 (Galβ1 → 3GlcNAc) carbohydrate chain, A-hexaglycosylceramides with types 1 and 2 (Galβ1 → 4GlcNAc) carbohydrate chains, a B-heptaglycosylceramide with a type 1 carbohydrate chain, and A-heptaglycosylceramides with type 1 and 2 carbohydrate chains. In addition several minor glycolipids having more than seven sugar residues were detected by thin-layer chromatography. The small intestine and pancreas had some distinct differences in their expression of the major fucolipids. The small intestine contained only glycolipids based upon type 1 carbohydrate chain while the pancreas had both type 1 and type 2 structures. The intestines contained mainly difucosyl compounds while the pancreas tissues contained both mono- and difucosyl glycolipids. Monofucosylglycolipids based on both types 1 and 2 saccharides were present in one pancreas while the other one contained only monofucosylcomponents based on type 1 chain. The ceramides of the intestinal glycolipids were found to be more hydroxylated (trihydroxy long-chain base, hydroxy fatty acids) compared to the pancreas glycolipids (dihydroxy long-chain base, non-hydroxy fatty acids).