Idopyranosiduronic acid

The conformation of nonsulfated L-idosyluronic acid residues is a controversial issue, especially on account of a possible role of the 2-O-sulfo substituent in determining the relative orientation of biologically relevant groups. However, the interproton coupling-constants observed for (nonsulfated) methyl a-o-idopyranosiduronic acid and dermatan sulfate are essentially the same as those of the sulfated L-iduronate resi-... 

Dichroic Behavior of Carboxyl and Amide Chromophores in Polysaccharide It is evident that the configurational differences of the uronic acid moiety are well reflected in the dichroic behavior of the polymer, and the carboxyl chromophore thus plays a significant role in the chiroptical properties of the molecules. Certain facts regarding carboxyl chromophores are apparent from this study a) monomeric CD properties are well reflected in the Cotton effect of the polymer b) similarities in A0 values (Table 11) between monomers and polymers containing similar uronic acids indicate the additivity of monomer contributions to polymer CD c) iduronic acid shows considerably larger CD than glucuronic acid, which may have some origin in the observed difference in the NMR behavior (29) of methyl a-D-idopyranosiduronic acid from uronic acid with normal C-1 conformation. This has been interpreted in terms of either an equilibrium between the C-1 and 1-C chair forms or adoption of a hybrid skew boat structure. 

The receptor-binding of high-uptake forms of lysosomal enzymes to human diploid skin fibroblasts has been demonstrated directly by using a sensitive assay for the bound enzyme. a-L-Iduronidase-deficient cells were incubated with human urinary a-L-iduronidase and the cell-associated enzyme was assayed with 4-methylumbelliferyl a-L-idopyranosiduronic acid. D-Mannose 6-phosphate greatly accelerated the dissociation of the bound enzyme, and during uptake of a-L-iduronidase the receptors were regenerated every few minutes, even in the absence of protein synthesis. 

Me glycoside, 2,2 -disulfate Methyl 2-0-sulfo-4-0-(2 -0-sulfo-a-D-glucopyrano-syl) -a-L-idopyranosiduronic acid C13H22O18S2 530.438 Md +28.1 (c, 0.26 in H2O) (as tri-Na salt). 

Phenyl a-L-idopyranosiduronic acid and the 4-methylumbelliferyl analogue, required for the assay of a-L-iduronidase, were obtained from a-L-idopyranose penta-acetate by standard condensations followed by saponification of the ester groups and platinum-catalysed oxidation at C-6. The synthesis of 5-azido-5-deoxy-L-idofuranurono-6,3-lactone derivatives is mentioned in... 

Chapter 9. A substrate used in the assay of L-iduronic acid 2-sulphate sulphatase was obtained from sodium heparinate by methanolysis followed by nitrosation. Disaccharide monosulphates presumed to contain D-(methyl a-L-idopyranosiduronate-2-sulphate)-(l 4)-2,5-anhydro-D-mannose were isolated by gel filtration. Brucine L-guluronate and o-mannuronate, on the other hand, were obtained by treatment with brucine of the barium salts of the acids formed on hydrolysis of alginic add. ... 

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