Bis-sulfated gangliotetraosylceramide from rat kidney.

A novel bis-sulfated tetraglycosylceramide containing N-acetylgalactosamine was isolated from the lipid extract of rat kidney. The isolation procedure involved extraction of lipids with chloroform/methanol, alkaline methanolysis, and column chromatographies with DEAE-Sephacel and silica beads. By infrared spectroscopy, proton magnetic resonance spectroscopy, periodate oxidation, solvolysis, chromium trioxide oxidation, and methylation analysis of the native and partially degraded compounds, the structure of this glycolipid is proposed to be (HSO3-3)Gal beta 1-3GalNAc beta 1-4(HSO3-3)Gal beta 1-4Glc beta 1-1Cer. The position of sulfate ester groups and the sequence of carbohydrates were further confirmed by methylation analysis and direct probe mass spectrometry after desulfation-trideuteriomethylation of permethylated glycolipids. The yield of this sulfoglycolipid was 5.5 nmol/g of tissue, which was about 25 and 50 mol %, respectively, of monosulfo-and bis-sulfogangliotriaosylceramide from rat kidney.