Periodate Oxidation Smith Degradation

A purified extracellular heteroglycan obtained from cultures of Cladosporium tricoides is composed of D-galactosyl, D-glucosyl, D-mannosyl, and L-rhamnosyl residues. Periodate oxidation. Smith degradation, and methylation analysis indicated that the polysaccharide (25) is highly branched. 

Methylation analysis of the tetra-arabinosides isolated from primary cell walls of tomato and sycamore indicates that the arabinosyl residues are terminal and 2- and 3-linked (71, 123). Akiyama and Kato (2) have studied the hydroxyproline arabinosides obtained from suspension-cultured cells of tobacco (Nicotiana tabacum). These workers used periodate oxidation (Smith degradation), methylation analyses, NMR, and optical rotation to show that the structure of the hydroxyproline tetra-arabinoside is Araf-(1 3)-Araf-(l - 2)-Arar(l - 2)-Arar(l - 4)-hydroxyproline. 

Monosaccharide residues containing vicinal hydroxyl groups are oxidized by periodate, and are subsequently removed in the reduction-hydrolysis step. Therefore, the positions to which such monosaccharide residues are linked can be located by methylation analysis performed before, and after, Smith degradation. Alternatively,59 the oxidized and reduced sample is methylated, the ether hydrolyzed, and the product realkylated with CD3I or CH3CH2I. This kind of procedure can have advantages over that first described. For example, methylation before the hydrolysis step hinders the acetal protection of hydroxyl groups that can occur in acid hydrolysis.7... 

What products would you expect from cellulose as a result of methylation analysis Periodate oxidation The Smith degradation The action of an alpha amylase ... 

JS) and of products of two successive periodate oxidation and Smith degradation stages (38). 

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