Glycolipid purified

Figure 6. Thin-layer chromatogram of the glycolipids purified from human saliva ("see Table VI for structures)...

Appreciable proportions of galactocerebrosides were found in the sea anemone Gyrostoma sp., the whole animal and its individual organs being studied the glycolipid was not, however, purified and studied in detail.75... 

Extensive purification of the glycosphingolipids present in the neutral fraction resulted in the isolation of three distinct glycolipids exhibiting Forssman antigenic activity (Table I, compounds 9,10,11). Thin-layer chromatographs of these glycolipids is illustrated in Fig. 1. Chemical analyses of the purified... 

Figure 2. Thin-layer chromatogram of purified glycolipid 11 (Table 1) and its enzymatic hydrolysis products...

N-acetyl (4,5,6,7,8,9-l c) neuraminic acid was obtained from Amersham, U.S.A. All other chemicals were reagent grade. Purified glycolipid standards and reagents for GLC analysis were kind gifts from Dr. Samar Kundu, Albert Einstein College. 

Lipid extracts (0.3ml) were dried under nitrogen, resuspended in a<15ii1 C M (1 1) and spotted on activated silica gel 60 plates with purified glycolipid standards GM3, GM2, lactosylceramide (LC) and glucosylceramide (GC) containing 10yg sialic acid each. 

Sialic acid was partially-purified from lipid extracts after hydrolysis in 0.05NHC1 (total sialic acid) or without hydrolysis (free sialic acid) as described in Methods. The amounts of gly-cosidically-bound sialic acid (total minus free) and free sialic acid were determined by the TBA assay. The hydrolysed samples were also analyzed using gas liquid chromatography by the method of Yu and Ledeen (15) and shown to possess essentially identical amounts of total sialic acid. However, the crude lipid extracts were too impure to make GLC the method of choice in the absence of extensive purification of the glycolipids. 

Glycolipid analysis. Gangliosides were extracted with chloroform-methanol (2 1), purified on Sephadex G-25 columns and separated into individual species by thin-layer chromatography as described previously (12). 

Thin Layer Chromatography. Two dimensional preparative TI was used to purify Thy-1 glycolipid. All experiments were performed using Silica Gel 60 TLC plates (E. Merck, Darmstadt, West... 

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