Uronic acids carbodiimide reduction

Reduction of uronic acids Uronic acids (UA) were converted to the corresponding neutral sugars (NS) by carbodiimide activation of the carboxyl groups followed by a reduction with NaBD4 according to the method of Kim and Carpita [5]. In order to achieve a complete reduction of the uronic acids the procedure was repeated once. 

Chemical modifications of the antigens were achieved by oxidation of the monosaccharide residues with periodate and reduction of the carboxyl groups of the uronic acid residues by the carbodiimide and borohydride methods, Fig. (IOC). The periodate oxidation was performed by a procedure described in the literature [37]. The reduction of the uronic acid residues of the antigen was performed by the carbodiimide (CMC) and sodium borohydride method [38], The oxidized and reduced types of antigens no longer reacted with the antibodies, Fig. (IOC). 

Glycuronans react with water-soluble carbodiimides to give products whose exact nature has not yet been established. However, they appear to be lactones or intramolecular esters, and can be reduced with sodium borohydride to give neutral monosaccharide residues corresponding to the original uronic acid residues. This particular reduction of glycuronans has been applied in acid-catalyzed hydrolysis in structural studies, as... 

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