Neuraminic acid detection

Fig. 3.—Mass Fragmentography of Methylated Neuraminic Acids. [Detection at m/e 274 A, disialosyl-lactosylceramide B, the disialosyl ganglioside isolated C, B after treatment with neuraminidase D, the fraction containing the trisialosyl ganglioside. Detection at m/e 330 E, the disialosyl ganglioside F, the trisialosyl fraction. The peaks identified are (1) the permethylated (terminal) N-acetylneuraminic acid, and (2) the 8-O-acetyl (8-O-substituted) derivative of the methylated N-acetylneuraminic acid. Conditions 1% of SE-30, at 240°. Reproduced, by permission, from Ref. 80.]...

The HpHb and the Hp-globin complexes can also be detected (R4) with rabbit antihemoglobin serum. The combination between Hp and anti-Hp is not influenced even if the neuraminic acid has been split off (L5, L6, P5, S3). That the antigenic structure of dog Hp is related to that of human Hp is evident from the fact that our potent antidog Hp serum cross-reacted with Hp in human sera and that our potent antihuman Hp serum cross-reacted with dog Hp. 

Among the gangliosides, GM4 [ct-NeuAc-(2 — 3)-/ -Gal-(l — 0)-Cer] has a relatively simple chemical structure. It has been detected in human and chicken brain and also (119) as a major ganglioside of mouse erythrocytes, chicken-embryonic liver, and egg yolk. With the help of the azidosphingo-sine glycosylation it has been synthesized very efficiently from the neuraminic acid-containing galactosyl donor 11a-/ (Table XI) (120-122). Similarly the thio isomer was obtained from lib-/ and (120,123) the positional isomer from llc-a. 

A substance later shown to be muramic acid (see Section IV,6) was clearly different from the product of Vi antigen, and, although the strain used in some of the Vi studies (Escherichia coli 5396/38) is one in which sialic acid has been detected, the properties of the Vi antigen are markedly different from the neuraminic acid pol3oner. Infrared spectra recorded for crystalline V-acetyl-neuraminic acid exhibit full detail and cannot be compared with that published for aminohexuronic acid, but that of the amorphous neuraminic acid polymer (colominic acid) is rather similar to that of the Vi antigen polymeric unit, since their functional groups are very similar. The relationship of these substances to the property of 0 -inagglutinability is discussed later (see p. 336). 

Nonulosaminic acids are found as constituents of certain water-soluble, lipid fractions (glycolipids) of animal tissues, being particularly associated with gangliosides as well as with more complex lipopolysaccharides. The detection and characterization of the nonulosaminic acid component in these mucolipids has been based upon one or more of the color reactions (see below) applied to the macromolecular material, followed by isolation therefrom of methoxyneuraminic acid after methanolysis. The question of whether or not one or more acylated forms of neuraminic acid are actually present in the mucolipid has still to be resolved. Svennerholm has reported the isolation of A-acetylneuraminic acid from brain gangliosides. 

The synthesis of a 4-methylumbelliferyl glycoside of A-acetyl-a-D-neuraminic acid has been reported for use as a substrate for the fluorometric detection and estimation of a-neuraminidase. ... 

An increased urinary excretion of free A-acetylneuraminic acid has been detected in patients with Salla disease, which is a newly reported type of lysosomal storage disorder.Patients appear to lack an iV-acetylneuraminyl lyase or some lysosomal enzyme responsible for the degradation of AT-acetyl-neuraminic acid. 

Free muramlc acid In human serum has been determined, as an Indicator of bacterial cell wall debris, by separation on a silica-based strong cation exchanger, post-column reaction with bls(l,10-phenanthroline)copper(II), and amperometrlc detection of the derived copper(I) species. Sensitive reversed-phase analyses of neuraminic acid and KDO (3-deoxy-D-manno-oct-2-ulosonlc acid) as their -nitrophenylhydrazone derivatives have been reported. 

Prothrombin, the precursor of thrombin, is present in plasma only in small amounts (0.2% of the protein content of plasma) and can be purified by acid precipitation by adsorption on magnesium hydroxide and fractionation with ammonium sulfate. The purified protein contains glucose (6.5%), neuraminic acid (5%), and unidentified amino sugars. A study of the amino acid composition reveals that the molecule contains 19 different amino acids. Prothrombin has only one N-terminal amino acid (alanine), and no carboxy C-terminal can be detected by hydrolyzing the molecule with carboxypeptidase A or B. Prothrombin is an ellipsoid molecule (119 A x 34 A) with a molecular weight of 62,700. On electrophoresis of plasma, prothrombin migrates between the a2- and the jS-globulin. 

Jhc and Vcc couplings have been calculated and measured by Serianni and co-workers for detection and quantification of acyclic keto, keto hydrate and enol forms of C-labelled A-acetyl-neuraminic acid. 

The other gangliosides listed in the table are minor components of the total ganglioside mixture. They differ in the size of the hydrophilic carbohydrate part and in the number of N-acetyl-neuraminic acid molecules. The different chromatographic behaviour, particularly in thin-layer chromatography allows their easy detection. A gangUoside with a simple structure has been isolated from horse erythrocytes (Yamakawa 1951 Klenk et al. 1952). It has been named haematoside and its exact structure determined. N-acetyl-neuraminic acid is substituted by N-glycolyl-neuraminic acid ... 

Sialic acid was the first virus receptor identified. Hirst and McClelland and Hare discovered that influenza virus is able to hemagglutinate and that adsorbed virus is eluted from erythrocytes on incubation at 37°C, indicating an enzymatic destruction of a receptor substance on the cells [1, 2]. When a similar enzymatic activity was subsequently detected in Vibrio cholerae cultures, the term receptor-destroying enzyme was introduced [3]. The substance released by the viral enzyme from soluble hemagglutination inhibitors was initially characterized as a carbohydrate of low molecular weight [4] and then identified in crystalline form as A-acetyl-o-neuraminic acid [5]. Thus, it was clear that the receptor determinant of influenza virus was sialic acid and that the viral enzyme was a neuraminidase. Furthermore, for the first time an important biological function of sialic acid had been identified. 

Muramic acid has been determined quantitatively by a procedure that involves its degradation to acetaldehyde via lactic acid. Acetaldehyde was measured spectrophotometrically, and other components present in hydrolysates of bacterial cell walls did not interfere with the determination. The analysis of natural and synthetic N- and O-acylated sialic acids by g.l.c. of the TMS ethers has been described. The 0-acyl groups were not lost when iV-trimethylsilyl-imidazole was used as the silylating reagent. A quantitative determination of neuraminic acid by g.l.c.-m.s. (using multiple ion-detection) has been reported. A modified periodate-resorcinol procedure, which avoids extraction of the... 

Glycoproteins containing sialic acid may be detected by staining with a cationic carbocyanine dye before and after digestion with neuraminidase a change in the colour of the stain from blue to red-purple indicates the presence of sialic acid. The n.m.r. spectra of iV-acetylneuraminic acid and its methyl ester in DMSO and in water have indicated that the acid exists predominantly in the /S-form in solution. The finding supports the assumption that 7V-acetyl-neuraminic acid, produced by the enzymic cleavage of its a-ketosides, leaves the catalytic site of Vibrio cholerae neuraminidase as the j3-anomer. 

Hara, S., Yamaguchi, M., Takemori, Y., and Nakamura, M., 1986, Highly sensitive determination of N-acetyl- and N-glycolyl-neuraminic acids in human serum and rat serum by reversed phase liquid chromatography with fluorescence detection, J. Chromatogr. 377 111-119. 

---