Mass spectrometry of sialic acids

G. P. Smirnova, N. V. Chekareva, O. S. Chizhov, B. M. Zolotarev, and N. K. Kochetkov, Mass spectrometry of sialic acids Peracetylated methyl esters of 5-acylamino-3,5-dideoxy-nononic and -heptonic acids, Carbohydr. Res., 59 (1977) 235-239. 

Gas-Liquid Chromatography and Mass Spectrometry of Sialic Acids... 

Kamerling, J. P., and Vliegenthart, J.F.G., 1982, Gas-liquid chromatography and mass spectrometry of sialic acids, in Sialic Acids (R. Schauer, ed.), Springer, New York, pp, 95-125. 

Reuter, G., and Schauer, R., 1986, Comparison of electron and chemical ionization mass spectrometry of sialic acids. Anal. Biochem. 157 39-46. 

Although the different methods for the analysis of sialic acids thus far described give some insight into the structure of these compounds, mass spectrometry permits unambiguous determination of the chain length and the number, type, and position of N- or O-acyl substituents in Neu derivatives. Thus, a variety of new and rare sialic acids have been discovered in the past few years, and the presence of known, mainly O-acetylated, sialic ac ids has been established in a variety of biological materials.34-37,62 85,94,95-97-96-10 -107-147-149... 

Several alternative methods for the determination of sialic acid in body fluids and tissues have been described. Most of these methods make use of the classic periodate-TBA assay in combination with purification using HPLC [13]. Another method makes use of fluorometric HPLC of sialic acids after derivatization with a fluorogenic compound [9]. The most promising new method for the determination of free sialic acid in urine (and probably also other body fluids and tissues) is the HPLC-tandem mass spectrometry method [19]. This method is rapid, accurate, and sensitive, and is more robust than earlier methods. The only disadvantage is the expensive equipment that is required, which makes it only economical for specialized metabolic laboratories. Since this equipment is used for many different metabolic assays, the investment is certainly warranted, and nowadays almost essential for any metabolic laboratory. 

Valianpour F, Abeling NG, Duran M, Huijmans JG, Kulik W (2004) Quantification of free sialic acid in urine by HPLC-electrospray tandem mass spectrometry a tool for the diagnosis of sialic acid storage disease. Clin Chem 50 403-409... 

Powell AK, Harvey DJ (1996) Stabilization of sialic acids in N-linked oligosaccharides and gangliosides for analysis by positive ion matrix-assisted laser desorption/ionization mass spectrometry. Rapid Commun Mass Spectrom 10 1027-1032... 

Mass spectrometry has been used successfully to establish the structure of sialic acids, and the type of their bonds in the oligosaccharide chain. For this purpose, the fragmentation of various derivatives containing both the cyclic and the acyclic forms of sialic acid has been comprehensively studied. The methyl esters of sialic acid methyl ketosides, obtained as a... 

Y. Miura, Y. Shinohara, J.-i. Furukawa, N. Nagahori, and S.-I. Nishimura, Rapid and simple solid-phase esterification of sialic acid residues for quantitative glycomics by mass spectrometry, Chem. Eur. J., 13 (2007) 4797 1804. 

These methods have their value in the relative ease of use and adaptation to large sample numbers. However, although tentative assignment of N- and 0-acyl substitutions can be made, the unequivocal determination of the structure of sialic acids must be made with mass spectrometry and n.m.r. spectroscopy as described in chapters F and G. 

Recently, the first proof for the occurrence of sialic acids in insects has been published (Roth et al., 1992). Neu5Ac was identified by mass spectrometry only... 

Great progress in our knowledge about sialic acids was made with the aid of gas-liquid chromatography (g.l.c.), mass spectrometry (m.s.), and n.m.r. spectroscopy. Structural analysis of the many different N- andO-acylated Neu derivatives occurring in Nature will be described in Sections IV,5 and 6. 

Mass Units of Characteristic Fragment-ions A-G Used for the Identification of Natural, N,O-Acylated Sialic Acids, and of the C7 and C8 Analogs of Neu5Ac and Neu5Gc as their Methyl Esters, Trimethylsilyl Ethers, by Mass Spectrometry"... 

Ten sialic-acid-containing oligosaccharides and four neutral oligosaccharides have been purified from the major glycoprotein fraction of hog, submaxillary-gland mucin. H-N.m.r. spectroscopy at 360 MHz, in combination with methylation analysis and mass spectrometry, allowed the determination of their structures, which are partial structures of a pentasaccharide (see Fig. 42) having blood-group A activity.221... 

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