Novel tri-and tetrasialosylpoly-N-acetyllactosaminyl gangliosides of human placenta: structure determination of pentadeca- and eicosaglycosylceramides by methylation analysis, fast atom bombardment mass spectrometry, and 1H NMR spectroscopy.
A series of highly polar neolacto series (poly-N-acetyllactosaminyl) gangliosides were isolated from human placenta tissue and purified by HPLC and preparative HPTLC. Two of these ganglioside fractions (G-12 and G-13) were analyzed by 500-MHz 1H NMR spectroscopy, GC-EIMS, +FAB-MS, and sequential exoglycosidase treatments. Their structures have been identified as being of the repeating N-acetyllactosamine type, multiply branched through GlcNAc beta 1----6/3 linkages, with every nonreducing Gal terminal alpha 2----3-sialosylated, as shown below. These are among the highest molecular weight glycosphingolipids whose detailed oligosaccharide structures are presently known. (formula; see text).
Levery
S B
SB
Biomembrane Institute, University of Washington, Seattle 98104.
Nudelman
E D
ED
Salyan
M E
ME
Hakomori
S
S
D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D005732:Gangliosides / Q000032:analysis*; D006801:Humans; D006868:Hydrolysis; D007790:Lactosylceramides / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D013058:Mass Spectrometry; D008745:Methylation; D008969:Molecular Sequence Data; D010920:Placenta / Q000032:analysis*
D005732:Gangliosides; D007790:Lactosylceramides; C047989:trisialosyllactosylceramide