Glycosphingolipids sulfated

Further investigations led the same group to increase the degree of sulfation on galactosylated dendrimers, based on the hypothesis that glycosphingolipid SGalCer... 

Sulfation of the carbohydrate chain occurs after the monosaccharide to be sulfated has been incorporated into the growing carbohydrate j chain. The source of the sulfate is 3 -phosphoadenosyl-5 -phospho-sulfate (PAPS, a molecule of AMP with a sulfate group attached to the 5-phosphate). Sulfotransferases cause the sulfation of the carbohydrate chain at specific sites. [Note An example of the synthesis of a sulfated glycosaminoglycan, chondroitin sulfate, is shown in Figure 14.11.] PAPS is also the sulfur donor in glycosphingolipid synthesis. [Note A defect in the sulfation process results in one of several autosomal recessive disorders that affect the proper development and maintenance of the skeletal system. This illustrates Ihe importance of the sulfation step.]... 

E. Vukelic, A. D. Zamfir, L. Bindila, M. Froesch, J. Peter-Katalinic, S. Usuki, and R. K. Yu, Screening and sequencing of complex sialylated and sulfated glycosphingolipid mixtures by negative ion electrospray Fourier transform ion cyclotron resonance mass spectrometry, J. Am. Soc. Mass Spectrom., 16 (2005) 571—580. 

Another group of the acidic glycosphingolipids are the sulfoglycosphingolipids (formerly called sulfatides ). This field is comprehensively reviewed in [6]. Most abundant in mammalian tissues is 3-0-sulfogalactosylceramide (O Fig. IS) which occurs, e. g., in human kidney, rat lung, and in the human central and peripheral nervous system. Also, lactosyl -sulfate ceramide is found in mammalian tissues, e. g., in human kidney and liver. Higher glycosylated molecules are present, e. g., in human kidney, and in the rat and human central and peripheral nervous systems. 

Synthesis of glycosphingolipids and sulfoglycosphin-golipids involves the addition of sugar and sulfate residues to ceramide from UDP-sugar derivatives or the activated sulfate donor 3 -phosphoadenosine-5 -phosphosulfate (Chapter 17), and appropriate transferases. These pathways are discussed in Chapter 16. Catabolism of sphingolipids is by specific lysosomal hydrolases. Several inherited disorders associated with the deficiencies of these enzymes are discussed below. 

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