Abstract
m In the course of studies on the fatty acid composition of brain sphingolipids, it was necessary to develop a procedure for the quantitative isolation of sulfatides. While studying the metabolism of galactolipids in rat brain, Radin, Lavin, and Brown (1) separated a sulfatide fraction from total lipids after their passage through Florisil (activated magnesium silicate) and mixed ion resins; no attempt was made to characterize the fraction obtained. In applying their procedure, we found that resinous material eluted with the sulfatides seriously interfered with the gas-liquid chromatographic analysis of the fatty acids of the sulfatides. Several other resins were tried, but we were unable h find any anion exchange resin stable to the mixtures of electrolytes and organic solvents used in the procedure. The simple and mild procedure devised by Lees, Folch, Sloane Stanley, and Carr (2)) based on the distribution of lipids between the two phases of a series of related solvent systems, did not give quantitative yields with cerebral white matter and practically no yield at all with gray matter. Long and Staples (3) reported a complete separation of cerebrosides and sulfatides from rat brain by chromatography on silicic acid, but, though we made many attempts, we never succeeded in reaching a complete separation with human material. In the method to be described, cerebrosides and sulfatides are isolated together by chramatography on silicic acid and then separated on a column of diethylaminoethylcellulose. Materials. Reagent grade methanol was dried with anhydrous sodium sulfate and NaOH-pellets and di5
Highlights
10 ml of chloroform-methanol 1:2 per gram of brain material
The elution of the lipids was followed by paper partition chromatography with tetrahydrofuran-diisobutylketone-water 45 :5:6 (v/v), as described by Beiss andArmbruster(5)
Cerebrosides and sulfatides were eluted with chloroform-methanol
Summary
10 ml of chloroform-methanol 1:2 per gram of brain material. The residue was re-extracted twice with 5 ml chloroform-methanol 1:l per gram of brain material. The upper phase contained, besides salt and low molecular organic materials, most of the disialogangliosides, a small percentage of total sulfatides, and very small amounts of phospholipids. Residue was extracted with chloroform-methanol 2 :1, and the extrawctas added tothe original lower phase.
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