Cerebrosides galactosyl

Central nervous system myelin is enriched in certain lipids. Table 4-1 lists the composition of bovine, rat, and human myelin compared to bovine and human white matter, human gray matter, and rat whole brain [1] (see Ch. 3). While there are no absolutely myelin-specific lipids, cerebroside (galactosyl ceramide) is the most typical of myelin. With the exception of early development,... 

We initially demonstrated that brain cerebrosides, galactosyl-ceramides containing hydroxy fatty acids (HFA) and nonhydroxy fatty acids (NFA), could be completely derivatized by reaction with 10% benzoyl chloride at 60°C for 1 hour (2). After removal of excess reagents by partition between hexane and alkaline aqueous methanol, the perbenzoyl derivatives were seen to separate into two completely resolved components (HFA and NFA... 

The glycosphingolipids (GSLs) are sugar-containing lipids built on a backbone of ceramide they include galactosyl- and glucosylceramide (cerebrosides) and the gangliosides. Their structures are described in Chapter 14. They are mainly located in the plasma membranes of cells. 

Hydrophobic and Hydrophilic Components of Membrane Lipids A common structural feature of membrane lipids is their amphipathic nature. For example, in phosphatidylcholine, the two fatty acid chains are hydrophobic and the phosphocholine head group is hydrophilic. For each of the following membrane lipids, name the components that serve as the hydrophobic and hydrophilic units (a) phos-phatidylethanolamine (b) sphingomyelin (c) galactosyl-cerebroside (d) ganglioside (e) cholesterol. 

Sulfatides Sulfoglycosphingolipids (sulfatides) are cerebrosides that contain sulfated galactosyl residues, and are therefore negatively charged at physiologic pH. Sulfatides are found predominantly in nerve tissue and kidney. 

Glycolipids are important constituents of the plasma membranes, of the endoplasmic reticulum, and of chloroplasts. The cerebrosides and their sulfate esters, the sulfatides, are especially abundant in myelin. In plant membranes, the predominant lipids are the galactosyl diglycerides.29 74 The previously described ether phospholipids (archaebacteria), ceramide arnino-ethylphosphonate (invertebrates), and sulfolipid (chloroplasts) are also important membrane components. 

A partial synthesis of cerebroside sulfate [ sulfatide, the glycoside of ceramide with galactose 3-sulfate, (90)] was achieved [90] by acylating the sphingosine galactosyl 3-sulfate (89) (obtained by basic hydrolysis of natural sulfatide) with palmitoyl chloride or D-2-acetoxypalmitoyl chloride (and subsequent basic hydrolysis of the... 

Klenk and Lohr81 have reported the isolation of cerebroside esters from human-brain material. One hydroxyl group of the D-galactosyl group, or of the sphingosine residue, is in covalent conjugation with long-chain fatty acids. 

Various cerebrosides to have been reported are the P-D-glucopyranosyl compound which is the major component of Penicillium cerebrosides, an a-galactosylated cerebroside, the ceramide asymmetric parts of which were made from lyxose, which is described in Chapter 24, and the P-galactosyl compound 22 which shows anti-viral activity. ... 

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. 

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