Human neutral glycolipids

An HPLC method for neutral glycosphingolipids was first designed for the analysis of human plasma glycolipids (3), which consist primarily of glucosylceramide, lactosylceramide, globo-triaosylceramide and globotetraosylceramide (globoside). 

Martensson, E. Neutral glycolipids of human kidney. Isolation, identification, and fatty acid composition. Biochim. Biophys. Acta, 1966, 116, 296-308. 

Figure IB. Thin-layer chromatogram of human and chicken neutral glycolipids...

Fig. 3 Separation of highly nonpolar neutral glycolipids in the human brain. The solvent system used for the TC-CCC was hexane/ ethanol/water (10 15 4) (A) and (5 4 3) (B). The upper phase (organic phase) was mobile. The revolution speed was controlled to run from 1500 to 700 rpm. The highest column pressure was 350 psi. A total of 5 mg of a neutral fraction of human brain lipids was loaded. Each fraction was spotted and developed on the HPTLC using chloroform/methanol/0.2% CaCl2 (90 12 1). Choi, cholesterol CS, cerebroside. SF, solvent front.

Fig. 11.3.3. HPLC separation of glycolipids from human erythrocytes. Chromatographic conditions column, stainless steel tube (5000 x 2.1 nun) packed with a pellicular silica gel packing with an average particle size of 27 /im mobile phase, 10 min gradient of 2-17% aqueous ethyl acetate in hexane flow rate, 2 ml/min detection, UV at 280 nm. The red blood cell neutral glycolipids were isolated from 5 ml of normal blood. Peaks 1, Glc-Cer 2, Lac-Cer 3, Gal-Lac-Cer 4, globoside. Reproduced from Ullman and McQuer (1977), with permission.

Four neutral glycolipids, as well as the gangliosides and Gj, were identified in the lipid fraction from the human transformed cell lines RSa, RSb, and... 

The genetics and biochemistry of some human blood-groups have been comprehensively reviewed. The structures of several neutral glycolipids and gangliosides in bovine erythrocyte membranes have been established by the results of acid hydrolysis, methylation, periodate and chromium(vi) oxide... 

Neutral glycolipids of human blood serum, spleen and liver. Nature (Lond.) 198,688 (1963). 

Martensson, E. On the neutral glycolipids of human kidney. Acta chim. scand. 17, 2356 (1963). 

Neutral glycosphingolipids have also been studied in human skeletal (8) and cardiac (9) muscle. In skeletal muscle, lacto-sylceramide is the predominant glycolipid (38.4%) followed by globotriaosylceramide (26.3%) and globoside (12.4%) while in heart, globoside predominates (43.0%) followed by globotriaosylceramide (32.0%). 

Most of the lipids of the neutral fraction were eluted at the solvent front when the chloroform/methanol/water solvent system, which is suitable for the separation of the acidic fraction, was used. We then tried solvent systems which can separate more hydrophobic lipids. Using the hexane/ ethyl acetate/ethanol/0.1% aqueous ammonia solvent system, we could separate phospholipids (Fig. 2B) and glycolipids (data not shown). A 5-mg amount of a neutral fraction from human brain lipids was applied to TC-CCC by using hexane/ethyl acetate/ethanol/0.1% aqueous ammonia (5 5 5 4). Phosphatidylcholine (PC), sphingomyelin (SPM), and lysophosphatidylcholine (lysoPC) were successively eluted. Phosphatidylethanolamine (PE) and lyso-phosphatidylethanolamine (lysoPE) and other minor phospholipid components were retained as the column contents with this solvent system. Cerebroside (fr. 28/36) and some... 

Cholesterol and cerebrosides were difficult to separate via the hexane/ethyl acetate/ethanol/0.1% aqueous ammonia system. Therefore we used another solvent system to separate less hydrophobic lipids. A 5 mg amount of a neutral fraction from human brain lipids was applied to TC-CCC by using hexane/ethanol/water at a volume ratio of 10 15 4 (Fig. 3). In Fig. 3, the orcinol staining shows the specific purple color for cerebroside (CS) and ALGLs, and a non-specific brown color for other lipids (not identified). Most of the phospholipids and glycolipids were retained in the column contents. Cholesterol was isolated from other lipids (frs. 38 3) (Fig. 3A). Cerebroside is eluted at frs. 60-72. 

The five major neutral glycosphingolipids of human plasma have been characterized and each has a structure which has been identified previously. One of these glycolipids, D-glucosylceramide, and possibly a second, lactosyl ceramide, exchange between plasma and erythrocyte pools. The conclusion is drawn in terms of the relative roles of carbohydrate and lipid moieties of the glycosphingolipids in maintaining that association with erythrocyte membranes. 

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