Fucose preparation

The glycosyl-linkage compositions of our three RG-II preparations were similar (Table 2) and corresponded to the relative sugar molar ratios obtained from compositional (TMS derivatives) analyses indicating that methylation was complete. Almost all the methyl ethers obtained could be attributed to known residues of the RG-II molecule (Figure 1) and our data were in accordance to that previously reported for RG-II from different plant origins [3,8,12,20,26]. The relative molar ratios of these "characteristic" methyl ethers (calculated on the basis of 1 residue of 3,4-linked fucose) were almost all in stoichiometric amounts (Table 3), confirming thus that our three preparations corresponded to the accepted model for RG-II. 

Relative molar ratios (calculated on the basis of 1 residue of 3,4-linked fucose) of methyl ethers characteristic for RG-II in the preparations isolated from fruit-derived products... 

SPS could be degraded by the cruder, aaikalus preparation Pectinex Ultra-SP, giving a product consisting mostly of the monomeric sugars xylose, galactose, fucose, arabinose and... 

Probably the most promising polymeric drug carrier system involves polysaccharide molecules. These are natural polymers and are often biodegradable to products that are useful to the host or easily eliminated by the host. Dextrans have been the most extensively used polysaccharide for macromolecular prodrug preparations (79). These materials are biocompatible and the in vivo fate is directly related to their molecular weight. Moreover these macromolecules can be easily targetted to the hepatocytes with D-mannose or L-fucose (20). 

D-galactose to D-galactonolactone in the presence of the coenzyme NAD+, is more specific and enzyme preparations are available for which the only other substrates are a-L-arabinose and /3-D-fucose. The generation of NADH is conveniently monitored at 340 nm and permits quantitation of the galactose ... 

It is of interest to note that we have obtained the same fully methylated L-fucose derivative from Morgan s hog mucin preparation (see p. 44) and it is indeed probable that the group substances from pepsin and hog mucin are identical in many details of their structure. 

A new method of stereoselective synthesis of thiodisaccharides by conjugate addition of 1-thio- D-glucose (8a) or 1-thio-a-L-fucose (30b) to an imsatura-ted carbohydrate molecule was also used for the preparation of o-glucopyrano-syl- and of L-fiicopyranosyl-thiodisaccharides [56]. 

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