Glycolipids Glucosylceramide

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). 

Characterization of saccharide unit. Ganglioside I was hydrolyzed by neuraminidase to a neutral glycolipid which was further cleaved by 0-galactosidase to become glucosylceramide. 

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. 

Inokuchi, J., Momosaki, K., Shimeno, H., Nagamatsu, A., and Radin, N. S. (1989). Effects of D-threo-PDMP, an inhibitor of glucosylceramide synthetase, on expression of cell surface glycolipid antigen and binding to adhesive proteins by B16 melanoma cells. J. Cell. Physiol. 141, 573—583. 

Chagasic sera did not differentiate between glycolipids with terminal p glucosyl or p galactosyl non-reducing units. They however discriminated between glucosylceramides with differences in the ceramide structure. These results suggest that antibody... 

The mechanisms by which the cofactors for degradation of glucosylceramide and galactosylceramide stimulate the respective enzymes is not yet known. Quantification of these cofactors by their capacity to enhance enzymic glycolipid hydrolysis in vitro must therefore rely entirely on practical experiences. These will be discussed with the respective assay systems. 

Glucosylceramide is known to be the precursor of all the major classes of glycosphingolipids in mammalian tissues, while its counterpart, galactosyl-ceramide (GL-lb or cerebroside) gives rise only to a small group of glycolipids. The metabolism of galactosylceramide is discussed later. 

The preparation of a glycosylceramide derived from 2,3 4,6-di-0-isopropylidene-P-valienamine as an analogue of glucosylceramide and of some carbaglycosylamides as glycolipid analogues have been described. 

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. 

In studies on human anti-thrombin, jS-D-glucosylceramide was found to complex firmly with anti-thrombin III. It was suggested that the antithrombin might act as a carrier for glycolipids. 

Increased levels of gangliosides, sulphatides, and neutral glycosylceramides have been found in the skeletal muscles of rabbits with experimental dystrophy when compared to controls. Data obtained from the in vitro synthesis of glycolipids in rabbit platelets have indicated that D-glucose is used mainly for the production of D-glucosylceramide since this glycolipid is common to all... 

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