Neuraminic acid hydrolysis

The partially methylated monosaccharides obtained on depolymerization of the permethylated sample are preferably analyzed as acetates by g.l.c.-m.s., as shown by Bjomdal and coworkers.41,42 The neutral sugars and the amino sugars obtained in acetolysis-acid hydrolysis are reduced, and acetylated for the analysis, and the amino-hexitol and the neuraminic acid residues are acetylated after methanolysis. Identification with the aid of g.l.c.-m.s. has been described for all of the common components of protein- and lipid-linked glycans and oligosaccharides from animal cells, namely, the neutral sugars,41-43 hexitols,44 hexosamines,29,43,45,46 aminohexitols,31,32 and neuraminic acids.33,34,47... 

Acid-labile linkages of carbohydrates are commonly those of furano-sidic sugar residues or of deoxy monosaccharides.50,63 Consequently, neuraminic acid and fucose residues, which occur as terminal monosaccharides of protein- and lipid-linked glycans, are removed by hydrolysis with a dilute acid. The linkages formed by these two sugar residues can conveniently be differentiated by subjecting a portion of... 

The neuraminic acids (also called sialic acids), which occur in the terminal positions of carbohydrate moieties of many glycoproteins and ganglio-sides, must be hydrolyzed under very mild conditions. For example, hydrolysis with 0.01 M hydrochloric acid for 30 min at 100° causes 20% decomposition of N-acetylneuraminic acid. Sialic acids are more tolerant to methanolysis they may also be removed enzymically. 

From the whole starfish were isolated three monosialoglycolipids whose carbohydrate chains contain glucose, galactose, arabinose, and N-glycolyl-neuraminic acid. From the results of partial hydrolysis with acid, methanoly-sis, methylation, and Cr03 oxidation, the following structures have been proposed for these sialoglycolipids. 

Cows milk contains at least seven oligosaccharides, five of which release lactose on acid hydrolysis. Two of these oligosaccharides yield neuraminic acid, in addition to lactose, and have the same RL>otase as the two oligosaccharides found in rat mammary gland by Trucco and Caputto. ... 

CMP-lV-acetyl neuraminic acid and oxocarbenium ion-like transition state in sialoside hydrolysis... 

Hydrolysis of Sialic Acid (Neuraminic Acid) Derivatives... 

The characteristic components of the gangliosides have proved to be the sialic acids (62b) (N-acylated neuraminic acids). In 1941, Klenk179 described the isolation of N-acetylneuraminic acid after hydrolysis of gangliosides. 

In gangliosides, the N-acylated neuraminic acids are linked gly-cosidically to the oligosaccharide moiety of the molecule the latter can be cleaved by hydrolysis (for example, with dilute acid or with... 

The preparation, X-ray crystal structure and ab initio calculation of the charge distribution of lV-(2-acetamido-3,4,6-tri-0-acetyl-2-deoxy-p-D-glucopyranosyl)-pyridinium chloride have been reported. The anomeric iV-(2,3,4,6-tetra-0-acetyl-D-glucopyranosyl)-4-dodecylpyridinium bromides were prepared as novel cationic surfactants. The panel of five substituted-pyridinium salts 15 were synthesized from the peracetylated glycosyl chloride of p-D-lV-acetyl-neuraminic acid and used to probe the mechanisms of enzymatic and non-enzymatic hydrolysis of neuraminides. " Detailed analysis of the solvolysis of Af-(2-deoxy-a- and p-D-glucopyranosyl)-4-bromoisoquinolinium tetra-fluoroborate in aqueous alcoholic solvents indicated Sjv2-like transition states. 

A new procedure for the quantitative analysis of the carbohydrate constituents of glycoproteins involves 1) simultaneous action of neuraminidase and neuraminic acid aldolase li) hydrolysis (4 M CF2CO2H, 125°, 1 h) and ill) capillary g.c. analysis of the derived 0-methyloxlme peracetates.Since a complete separation of all... 

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