Characterization of neutral blood group B-active glycosphingolipids of rat gastric mucosa. A novel type of blood group active glycosphingolipid based on isogloboside.

The blood group active glycosphingolipids of rat gastric mucosa have been investigated. Only blood group B active structures were found, two of which have been structurally characterized by monoclonal antibodies, mass spectrometry, permethylation analyses, proton NMR spectroscopy, and exoglycosidase digestions. A six-sugar compound based on a gangliotetraosylceramide core was isolated and shown to have the following structure: (Formula: see text). The same compound was recently isolated from rat bone marrow cells and characterized by Taki et al. (Taki, T., Kimura, H., Gasa, S., Nakamura, M., and Matsumoto, M. (1985) J. Biol. Chem. 260, 6219-6225). The possible precursor compounds of this structure, gangliotriaosylceramide and gangliotetraosylceramide, were also found in the gastric mucosa. A seven sugar compound, based on isogloboside, was isolated from the gastric mucosa and shown to have the following structure: (formula; see text) The latter compound is novel and extends the list of different types of core structures found for blood group glycolipids. The epithelial cells of the stomach are unique among the cells lining the gastrointestinal tract in having blood group active glycolipids based on ganglio- and isogloboseries core structures.