Saccharides oxidation

Even if the main focus on the research activities were directed towards structural studies on carbohydrates of natural origin, the synthesis of model substances, deriva-tization of oligo- and poly-saccharides, oxidation, and reduction of carbohydrates, and identification of the products all were performed during this time. 

In contrast to L-iduronic acid residues, most of which are sulfated at C-2, D-glucuronic acid residues in heparin and heparan sulfate are largely or exclusively nonsulfated. This was especially proved by their susceptibility to periodate oxidation,123 and through characterization of D-glucuronic acid-containing di- and tetra-saccharides from deamina-tive104 109 110 138 or heparinase - heparanase cleavage137,145 of heparin. 

These authors showed that the time required to achieve quantitative uptake of periodate ion varied from starch to starch. The oxidation time for a simple saccharide cannot therefore be taken as a standard for starch. 

Oxidative stress and inflammation are elevated in hemodialysis patients, which, at least partly, might be initiated by intravenous iron administration. Thus, Tovbin et al. [377] showed that the administration of iron saccharide to hemodialysis patients increased the blood level of oxidized proteins. Similarly, an increase in the levels of free ( nontransferrin-bound or labile ) iron has been shown in the plasma of hemodialysis patients [378] including patients after intravenous iron saccharate infusion [379]. 

The D-galactosyl residues are the same as in disaccharide 33, and the fact that ribitol is substituted at 0-2 was evident from the methyl-ation analysis. Finally, a nonreducing tetrasaccharide was obtained, containing D-galactose, 2-acetamido-2-deoxy-D-galactose, and ribitol residues in the proportions 2 1 1. From these results, and periodate-oxidation studies, structure 36 was proposed for the neutral hexa-saccharide. 

The mucic acid test is now only of historical interest. It depends on the oxidation of galactose or saccharides containing a galactose residue, such as lactose, with nitric acid to yield mucic acid. Mucic acid is highly insoluble in water, while the isomeric dicarboxylic acids yielded by other sugars are soluble. Mucic acid may be identified by its characteristic thallium salt. 

Constitutional studies have broadly followed the pattern of methyla-tion of the unsubstituted alcoholic groups in a carbohydrate, hydrolytic or oxidative disruption of the molecule and identification of the resulting methylated fragments. In this way methyl ethers have been invaluable in the determination of the ring structures of the monosaccharides and in the elucidation of the constitutions of the more complex saccharides. 

Meyer A, Ptihler A, Niehaus K (2001) The lipopoly saccharides of the phytopathogenXanthomonas campestris pv. campestris induce an oxidative burst reaction in cell cultures of Nicotiana taba-cum. Planta 213 214-222... 

However, still a limited number of analytes can be sensed. It is very challenging to realize nanosensors for carbon dioxide, ammonia, saccharides, etc. but micrometersized particles can be prepared and used in composite materials. The nanosensors for neurotransmitters, nitrogen oxides and many other important species are yet to be established. 

Lowenstein CJ, Alley EW, Raval P, et al. Macrophage nitric-oxide synthase gene-2 upstream regions mediate induction by interferon-gamma and lipopoly-saccharide. Proc Natl Acad Sci USA 1993 90 9730-9734. 

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