NANA N-Acetylneuraminic acid

Gangliosides branched oligosaccharide chains terminating in the 9-carbon sugar, sialic acid (N-acetylneuraminic acid, NANA)... 

N-Acetvlneuraminic Acid Aldolase. A new procedure has also been developed for the synthesis of 9-0-acetyl-N-acetylneuraminic acid using the aldolase catalyzed reaction methodology. This compound is an unusual sialic acid found in a number of tumor cells and influenza virus C glycoproteins (4 ). The aldol acceptor, 6-0-acetyl-D-mannosamine was prepared in 70% isolated yield from isopropenyl acetate and N-acetyl-D-mannosamine catalyzed by protease N from Bacillus subtilis (from Amano). The 6-0-acetyl hexose was previously prepared by a complicated chemical procedure (42.) The target molecule was obtained in 90% yield via the condensation of the 6-0-acetyl sugar and pyruvate catalyzed by NANA aldolase (Figure 6). With similar procedures applied to KDO, 2-deoxy-NANA and 2-deoxy-2-fluoro-NANA were prepared from NANA. 

N-Acetylneuraminic acid N-Acetylneuraminic acid (NANA) is a member of the family of sialic acids, each of which is acylated at a different site. These compounds are usually found as terminal carbohydrate residues of oligosaccharide side chains of glycoproteins, glycolipids, or, less frequently, of glycosaminoglycans. The]... 

Further developments are shown in Figure 4. On the basis that glucosamine reacted with pyruvic acid in the presence of alkali to yield pyrrole-2-carboxylic acid, in 1% yield, Gottschalk (21) proposed that sialic acid was formed by an aldol condensation reaction between N-ace-tylglucosamine and pyruvic acid. Kuhn and Brossmer (15) and Zilliken and Glick (22) showed that the reverse reaction also took place under alkaline conditions. Cornforth, Firth, and Gottschalk (23) synthesized crystalline N-acetylneuraminic acid (NANA) from N-acetylglucosamine and oxaloacetic acid (pH 11, 20°C). Under conditions less subject to misinterpretation, Heimer and Meyer (24) found that Vibrio cholerae enzymes cleaved NANA into an N-acetylhexosamine and pyruvic acid. 

In considering the application of enzyme catalysis to DCC, we were encouraged by the thermodynamic resolution of a dynamic mixture of aldol products by Whitesides and co-workers through the use of a broad-specificity aldolase to lead to reversible formation of carbon-carbon bonds under mild conditions.35 For the current investigation36 we chose a related enzyme, N-acetylneuraminic acid aldolase (NANA aldolase, EC 4.1.3.3), which catalyzes the cleavage of N-acetylneuraminic acid (sialic acid, 27a) to A-acetylmannosamine (ManNAc, 28a), and sodium pyruvate 29 in the presence of excess sodium pyruvate, aldol products 27a-c are generated from... 

Acetyl-CoA ADP Ala AMP ATP BHK CC9C10 CHO CHSE CMP-NANA CoQ CoQH2 DNA acetyl-coenzyme A adenosine diphosphate alanine adenosine monophosphate adenosine triphosphate baby hamster kidney cell line hybridoma cell line Chinese hamster ovary cell line Chinook salmon embryo cell line cytosine monophosphate-N-acetylneuraminic acid coenzyme Q dihydroubiquinone deoxyribonucleic acid... 

N-Acetylneuraminic acid (derived from CMP-NANA) often forms g branches from the main chain. 

Figure 6-15. Synthesis of sphingolipids. NANA = W-acetylneuraminic acid G/c = glucose Gal = galactose GalNAc = N-acetylgalactosamine PIP = pyridoxal phosphate FA = fatty acyl groups derived from fatty acids = hydrophobic chains of ceramide. The dashed box contains the portion of ceramide derived from serine.

The structure of other natural gangliosides isolated from normal-human and bovine nervous-tissues was determined. These individual gangliosides have, in covalent conjugation, more than one residue of N-acetylneuraminic acid (NANA) that can be split off enzymically with neuraminidase, giving2068 the fundamental ganglioside-G/. 

N-Acetylneuraminic Acid Aldolase Origin microorganisms Unitika N-Acetylneuraminic Acid Aldolase (Nana-Ald)... 

N-Acetylmaimosamine is the precursor of N-acetylneuraminic acid (NANA, a sialic acid) and GDP-mannose is the precursor of GDP-fucose (see Fig. 30.8). The negative charge on NANA is obtained by the addition of a 3-carbon carboxyl moiety from phosphoenolpyruvate. 

C,H,7N0 Mr 267.25. An amino sugar acid isolated from gangliostdes and named by Klenk. N. is unstable and cyclizes spontaneously to furnish a pyrroline derivative. However, it is widely distributed in N- and O-acylated forms. N-Acetylneuraminic acid (NeuSAc, Neu/VAc, NANA) C,H NO Mr 309.27, mp. 185-187°C, [a]o -33 (HjO). 

When ceramide combines with oligosaccharides and N-acetylneuraminic acid (NANA, also known as siaUc acid), the gan-gliosides are formed. Gangliosides comprise approximately 5% of brain lipids. 

Fig. 7. Positive and negative ion mass spectra of Analyte-5 (100 fmol/well) with DHB (A and D), G2CHCA (B and E) and G3CA (C and F) using MALDI-QIT-TOF mass spectrometer. Dissociation of N-acetylneuraminic acid (NANA sialic add) was suppressed using G2CHCA or G3CA (B, C, E and F).

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