Smith degradation methylation structural analysis

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. 

The methods used for structural analysis of (4-0-methylglucurono)xylans have also been applied to the arabinogalactans from larch wood. They include methylation, partial hydrolysis, and Smith degradation. In addition, Barry degradation has found extensive use. Because of the few, detailed, structural investigations so far reported, and because of the complicated nature of the polysaccharides, each of the four species studied will be discussed separately. 

Autohydrolysis of H. holstii Q-phosphonomannan (mannose 5) liberates a pentasaccharide monophosphate of the apparent structure given in Figure 3. The structure of the dephosphorylated oligosaccharide was deduced from a methylation analysis (59) and accords with earlier Smith degradations of the intact biopolymer... 

K62 (23), have been elucidated, mostly using a combination of methylation analysis. Smith degradation, partial hydrolysis with acid, and H n.m.r. spectroscopy. In some cases e.g. Klebsiella serotypes K13, K25, and K37), depolymerization of the polysaccharides was accomplished by glycanase activities associated with particles of Klebsiella bacteriophages. Serological cross-reactions also revealed similarities in the structures of certain capsular polysaccharides for example, the polysaccharide from Klebsiella serotype K13 (18) cross-reacted with that from Klebsiella serotype K2, which has an identical structure except for the absence of the terminal 3,4-0-(l-carboxyethylidene)-P-D-galactopyranosyl residue. 

A glycopeptide (mol. wt. 1.3 x 10 ), containing L-fucose, D-mannose, D-glucose, and asparagine, has been isolated from the products of proteolysis of the lima bean lectin Phaseolus lunatus). Methylation analysis. Smith degradation, and subsequent degradation by specific glycosidases has resulted in the tentative proposal of a structure (5). 

The complete structures of the carbohydrate units of three other glycopeptides from ovalbumin (62—64) have been established, using a combination of sequential digestion with glycosidases. Smith degradation, selective acetolysis, and methylation analysis. ... 

The preferential synthesis of different polysaccharides by specific morphological types of Sporothrix schenckii has been reported. Thus, yeasts synthesize rhamnomannans containing monorhamnosyl side-chains, conidia or conidia-forming mycelia synthesize rhamnomannans with dirhamnosyl side-chains, and unsporulated mycelia synthesize galactomannans or mannans that are readily excreted into the culture medium. A combination of methylation analysis. Smith degradation, and n.m.r. spectroscopy was used to deduce the structure (25) for the D-mannan core of S. schenckii galactomannan. 

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