Periodate-oxidized polysaccharide

Protein molecule containing periodate-oxidized polysaccharides (having aldehyde groups)... 

Figure 23.9 Reaction of adipic acid dihydrazide with (strept)avidin produces a hydrazide derivative that is highly reactive toward periodate-oxidized polysaccharides.

The Smith degradation4 involves reduction of the periodate-oxidized polysaccharide with borohydride, followed by mild hydrolysis with acid. (The periodate oxidation has already been treated in Section 111,1, p. 200.) The modified sugar residues contain acyclic acetal groupings, which are hydrolyzed much faster than the glyco-sidic linkages. The product therefore contains small fragments (such... 

Sometimes, it is more feasible, however, to degrade periodate-oxidized polysaccharides so that unattacked residues are split off as free, reducing sugars. This can be achieved by a graded hydrolysis of the polyaldehyde with sulfurous acid. The conditions for an optimum yield of the desired products must be carefully chosen. ... 

An improved way of utilizing the method of periodate oxidation for determining the nature of the linkages in polysaccharides was provided by Smith and coworkers. They realized that, if the periodate-oxidized polysaccharide were reduced to the corresponding alcohol, the resulting fragments, on hydrolysis, would be indicative of the types of linkage present in the parent polymer. This scheme is shown in Fig. 1. Such an approach was used in a study of the dextrans from 6 different strains of L. mesente-... 

When coupled, with cooling, with phenylhydrazine, the periodate-oxidized polysaccharides containing two or more adjacent hydroxyl groups (for example, cellulose, starch, dextrin, and dextran) yield bright-yellow phenyl-hydrazones within a few minutes. ... 

Formazans of Periodate-oxidized Polysaccharides and Their Derivatives... 

Fio. 10.— Mechanism for the Effect of Alkali on Periodate-oxidized Polysaccharides (where R and R = the remaining portions of the polysaccharide molecule). 

A prerequisite for this technique is that a portion of the sugars are resistant to periodate oxidation. The most commonly used procedure is the Smith degradation (Goldstein et al., 1965) where the periodate oxidized polysaccharide is reduced to the polyalcohol and then subjected to mild acid hydrolysis. Acyclic acetals are hydrolyzed more rapidly than glycosidic linkages thus it is possible to generate oligomeric products that can be isolated and characterized. 

DifiBculty is sometimes experienced in hydrolyzing periodate-oxidized polysaccharides with acid, because they contain stable, anhydro rings. If, however, the periodate-oxidized polysaccharide is first reduced to its corresponding polyalcohol, fragments characteristic of structural units in the parent polysaccharide may readily be obtained from the polyalcohol on hydrolysis with dilute acid. When this improved degradative... 

M. F. Ishak and T. (1. ) Painter, Formation of interresidue hemiacetals during the oxidation of polysaccharides by periodate ion, Acta Chem. Scand., 25 (1971) 3875-3877 M. F. Ishak and T. (1. ) Painter, Interresidue lactones formed by treatment of periodate-oxidized polysaccharides with aqueous bromine, Acta Chem. Scand, 27 (1973) 1321-1327. 

G. G. S. Dutton, K. B. Gibney, G. D. Jensen, and P. E. Reid, The simultaneous estimation of polyhydric alcohols and sugars by gas-liquid chromatography. Applications to periodate oxidized polysaccharides, J. Chromatogr., 36 (1968) 152-162. 

V. C. Barry and P. W. D. Mitchell, Properties of periodate-oxidized polysaccharides. PV. The products obtained on reaction with phenylhydrazine, J. Chem. Soc., (1954) 4020 023. 

Periodate-oxidized polysaccharides are sensitive to alkaline degradation but lose this property on reduction of the aldehydic groups to alcohols or on their oxidation to carboxylic acids with chlorous acid or bromine. 

A related t5q>e of degradation (Smith degradation) involves borohydride reduction of the periodate-oxidized polysaccharide, followed by acid hydrolysis. Fragments of the oxidized units in the polysaccharide appear as alcohols in the hydrolysis products. These can be identified and related to the structure of the original polysaccharide, affording similar structural evidence to the Barry degradation. 

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