Amino nonulosonic acids

Three 3-deoxynonulosonic acids containing amino groups are known. The most abundant of these is 5-amino-3,5-deoxy-D- /yc ro-D-ga/acto-nonulosonic acid (neuraminic acid, 27), which occurs in different extracellular polysaccharides. Some of these, like colominic acid from E. coli K1, are homopolysaccharides. Neuraminic acid is generally A-acetylated and, as in the animal glycoconjugates, has only been found in the a-pyranosyl form (27). It also occurs in some LPS, for example those from some Rhodobacter... 

Sialic acids are a family of nine-carbon acidic monosaccharides based on 3-deoxy nonulosonic acid (Fig. 17.4, also see Chapter 5). In 1952, the biochemist Gunnar Blix introduced the term sialic acid from the Greek aaXia (salia) or saliva after isolating this molecule from the salivary gland mucin. Sialic acid is now the generic term for the family that includes derivatives with a C5-amino substituent called neuraminic acid. Neu5Ac (5) is the type of sialic acid found in humans [47],... 

R = H 5-Amino-3,5-dideoxy-D-g/ycero-D-ga/acto-nonulosonic acid (Neuraminic acid)... 

Variants of keratan sulfate in which other neutral sugars occur and in which there is more than 1 mole of sulfate ester per disaccharide repeating unit are known. Keratan sulfate has also been found to contain smaller amounts of neutral monosaccharides, such as D-mannose and L-fucose, and 5-amino-3,5-dideoxy-D-gZj/cero-D-gcZacto-2-nonulosonic acid. 

I (5-amino-3,5-dideoxy-D-giyccro-D-golacto-2-nonulosonic acids, abbreviation Neu). 

Dideoxy-5-[ (hydroxyacetyl) amino J-d-g ycero-D-g3.l3cto-2-nonulosonic acid, 9CI. Porcine sialic acid. NGNA [1113-83-3]... 

Me ycoside, 4,5,7,8,9-penta-Ac, benzyl ester, D-321 3-Deoxy-D-g/ cero-i>gaiacto-2-nonulosonicadd (3-Pyranose-ybrm, D-321 3-Deoxy-D-g/ cero-i>gaiacto-2-nonulosonic acid, D-321 3-Deoxy-D-mawio -oct-2-enono-1,4-lactone, D-329 3-Deoxy-a-D-mawio -2-octulopyranosonosyl-(2 3)-2-amino-2-deoxy-(3-D-glucopyranosyI-(l ->Q-2-amino-2-deoxy-i>glucose a-Pyranose-ybrm N.N -Di-Ac, D-322... 

A non-competitive inhibitor (mol. wt. 3.8 x 10 ) of jS-o-glucuronidase has been isolated from human saliva by ion-exchange chromatography and gel filtration. It contains fucose (4.9%), hexose (16.6%), 2-amino-2-deoxyhexose (15.7%), 5-amino-3,5-dideoxy-D- (ycer< -D- a/acrn-2-nonulosonic acid (12.8%), and protein (46.7%). The inhibitor either is derived from serum or simulates the antigenicity of components therein. 

Matrices containing neuraminic acid (5-acetamido-3,5-dideoxy-D-g/yceru-D-ga/acru-2-nonulosonic acid) residues have been prepared by reaction of 2-amino-ethylamides of the 2-hydroxyethyl, 2-aminoethylaminocarbonyImethyl, and 2-aminoethyl a-ketosides of the acid with agarose cyclic imidocarbonate to give... 

The sulphatase A (mol. wt. 1.07 x 10 ) from bovine liver is a glycoprotein containing D-galactose (8), o-mannose (14), 2-amino-2-deoxy-D-glucose (18), and terminal, non-reducing 5-acetamido-3,5-dideoxy-D- /jceru-D- a/acro-2-nonulosonic acid (8 moles mole ), and traces of L-fucose and D-glucose. The implications of studies of this enzyme to metachromatic leukodystrophy were discussed. 

Sialic acids comprise a family of derivatives of neuraminic acid (5-amino-3,5-dideoxy-D-g/jcero-D-ga/ cto-nonulosonic acid) occurring widespread in nature, especially in the animal kingdom. From an evolutionary point of view, they probably have a long history, dating back to precambrian times, as they have already been found in Echinodermata (chapter B). It took a number of years (1936-1962) to establish the structure of N-acetylneuraminic acid by chemical and enzymic means, as has been reviewed by Gottschalk (1972), Ledeen and Yu (1976) and Tuppy and Gottschalk (1972). 

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