Glucan periodate oxidation

Kobayashi, M., and Ichishima, E. (1991) Application of periodate oxidized glucans to biochemical reactions./. Carbobydro Chem. 10, 635-644. 

In 1954, Jeanes et al.5 reported the formation of glucan(s) by 96 strains of bacteria that were primarily Leuconostoc strains. (There is a question here as to whether they are strains or species, particularly with regard to the formation of different kinds of polysaccharides. The classification of the time was to place them into one species, mesenteroides, that had several different strains. This classification stands today.) The polysaccharides were characterized by various properties such as optical rotation, viscosity, periodate oxidation profile, and physical appearance after alcohol precipitation. The latter were observed to have different appearances, which were described by Jeanes et al.5 in various qualitative terms such as pasty, fluid, stringy, tough, long, short, flocculent, and so on. These differences in appearance provided an early suggestion of differences in structure (see Table I). Both water-soluble and water-insoluble polysaccharides were formed, and some strains seemed to form more than one kind of polysaccharide, as judged by their water solubility and by differences in the amount of alcohol needed to precipitate them. 

Pachyman, a glucan obtained from Poria cocos, was inactive,112 whereas pachymaran, obtained by debranching pachyman through periodate oxidation and mild hydrolysis, was found effective against mouse sarcoma.112 113 0-(Carboxymethyl)ation of pachyman gave an... 

An alternative procedure for estimation of the number-average d.p. of (l- 4)-a-D-glucans has become apparent from work with partly periodate-oxidized amylose (see p. 266). This method depends on the fact that, when an average of one n-glucose residue per chain has been oxidized, the conversion into n-glucose by aZpba-amylase-free glucoamylase is only 50 . This is likely to become the preferred method for... 

TABLE 3- Periodate oxidation of the cell wall glucan of Pyricularia oryzae. 

The simplest possible structure proposed for the cell wall glucan of Pyricularia oryzae, based on the results of methylation, periodate oxidation and fragmentation analysis is shown in Fig. 1. 

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