N-Acetylneuraminic acid, the most common of the sialic acids
Sialic acids are a class of alpha-keto acid sugars with a nine-carbon backbone.[1] The term "sialic acid" (from Greek σίαλον (síalon) 'saliva') was first introduced by Swedish biochemist Gunnar Blix in 1952. The most common member of this group is N-acetylneuraminic acid (Neu5Ac or NANA) found in animals and some prokaryotes.
Sialic acids are found widely distributed in animal tissues and related forms are found to a lesser extent in other organisms like in some micro-algae,[2] bacteria and archaea.[3][4][5][6] Sialic acids are commonly part of glycoproteins, glycolipids or gangliosides, where they decorate the end of sugar chains at the surface of cells or soluble proteins.[7] However, sialic acids have been also observed in Drosophila embryos and other insects.[8] Generally, plants seem not to contain or display sialic acids.[9]
In humans, the brain has the highest sialic acid content, where these acids play an important role in neural transmission and ganglioside structure in synaptogenesis.[7] More than 50 kinds of sialic acid are known, all of which can be obtained from a molecule of neuraminic acid by substituting its amino group or one of its hydroxyl groups.[1] In general, the amino group bears either an acetyl or a glycolyl group, but other modifications have been described. These modifications along with linkages have shown to be tissue specific and developmentally regulated expressions, so some of them are only found on certain types of glycoconjugates in specific cells.[8] The hydroxyl substituents may vary considerably; acetyl, lactyl, methyl, sulfate, and phosphate groups have been found.[10]
Neuraminic acid (Neu), the N- or O-substituted derivatives of which form most sialic acids
^ ab
Varki, Ajit; Roland Schauer (2008). "Sialic Acids". in Essentials of Glycobiology. Cold Spring Harbor Press. pp. Ch. 14. ISBN 9780879697709.
^Wagstaff, Ben (2018). "Identification of a Kdn biosynthesis pathway in the haptophyte Prymnesium parvum suggests widespread sialic acid biosynthesis among microalgae". Journal of Biological Chemistry. 293 (42): 16277–16290. doi:10.1074/jbc.RA118.004921. PMC 6200933. PMID 30171074.
^Ajit, Varki (2017). "Sialic Acids and Other Nonulosonic Acids". Sialic acids and other nonulosonic acids." Essentials of Glycobiology. Cold Spring Harbor Laboratory Press. doi:10.1101/glycobiology.3e.015 (inactive 31 January 2024). PMID 28876847.{{cite book}}: CS1 maint: DOI inactive as of January 2024 (link)
^Kleikamp, Hugo (2020). "Tackling the chemical diversity of microbial nonulosonic acids – a universal large-scale survey approach". Chemical Science. 11 (11): 3074–3080. doi:10.1039/c9sc06406k. PMC 8157484. PMID 34122812.
^Lewis, Amanda (2009). "Innovations in host and microbial sialic acid biosynthesis revealed by phylogenomic prediction of nonulosonic acid structure". Proceedings of the National Academy of Sciences. 106 (32): 13552–13557. Bibcode:2009PNAS..10613552L. doi:10.1073/pnas.0902431106. PMC 2726416. PMID 19666579.
^Schauer, Roland (2018). "Exploration of the Sialic Acid World". Adv Carbohydr Chem Biochem. Advances in Carbohydrate Chemistry and Biochemistry. 75 (75): 1–213. doi:10.1016/bs.accb.2018.09.001. ISBN 9780128152027. PMC 7112061. PMID 30509400.
^ abWang, B.; Brand-Miller, J. (2003). "The role and potential of sialic acid in human nutrition". European Journal of Clinical Nutrition. 57 (11): 1351–1369. doi:10.1038/sj.ejcn.1601704. PMID 14576748.
^
Varki, Ajit; Roland Schauer (2008). "Sialic Acids". in Essentials of Glycobiology. Cold Spring Harbor Press. pp. Ch. 14. ISBN 9780879697709.
^Schauer R. (2000). "Achievements and challenges of sialic acid research". Glycoconj. J. 17 (7–9): 485–499. doi:10.1023/A:1011062223612. PMC 7087979. PMID 11421344.
Sialicacids are a class of alpha-keto acid sugars with a nine-carbon backbone. The term "sialicacid" (from Greek σίαλον (síalon) 'saliva') was first...
derivatives of neuraminic acid are collectively known as sialicacids, the predominant form in mammalian cells being N-acetylneuraminic acid. The amino group bears...
transports the charged sugar, N-acetylneuraminic acid (sialicacid), out of lysosomes. The mutation causes sialicacid to build up in the cells.[citation needed]...
binding to the APN in the presence of the sialicacid. Feline coronavirus infections are therefore sialicacid dependent. The Porcine epidemic diarrhea...
Siglecs (Sialicacid-binding immunoglobulin-type lectins) are cell surface proteins that bind sialicacid. They are found primarily on the surface of immune...
sialicacid groups. Sialicacids are found on various glycoproteins at the host cell surface. The virus then moves from sialicacid group to sialic acid...
3'-sialyllactose) and the carboxylate group of the sialicacid. Since sialoadhesin binds sialicacids with its N-terminal IgV-domain, it is also a member...
bind to α2,6 linked sialicacids, it might cross the species barrier and infect humans. Swine tissues express both forms of sialicacid and can be coinfected...
tissues), the most important being the capsular polysaccharide (rich in sialicacid) and a pore-forming toxin, β-hemolysin. Today it is considered that GBS...
glycosidic linkages of neuraminic acids: Hydrolysis of α-(2→3)-, α-(2→6)-, α-(2→8)- glycosidic linkages of terminal sialicacid residues in oligosaccharides...
polysaccharide chains. These polysaccharide chains are branched with sialicacid residues. Sialicacid is a monosaccharide carbohydrate. Various forms of transferrin...
proteins on the surface of the envelope, which bind to cells that contain sialicacid receptors on the surface of the cell membrane. For N1 subtypes with the...
prefers to bind to alpha-2,3 sialicacid receptors, while the human influenza hemagglutinin prefers to bind to alpha-2,6 sialicacid receptors. This means that...
protein, it binds to N-acetyl-D-glucosamine and sialicacid. WGA has also been shown to interact with sialicacid residues on oligosaccharides. Succinylated...
more sialicacids (e.g. N-acetylneuraminic acid, NANA) linked on the sugar chain. NeuNAc, an acetylated derivative of the carbohydrate sialicacid, makes...
CD33 or Siglec-3 (sialicacid binding Ig-like lectin 3, SIGLEC3, SIGLEC-3, gp67, p67) is a transmembrane receptor expressed on cells of myeloid lineage...
Polysialic acid (polySia) is polymer of linearly repeating monomer units of α2,8- and α2,9-glycosidic linked sialicacid residues. Sialicacid refers to...
NK cells is inhibited by the expression of sialicacids on the tumor cell surface. Removal of sialicacid residues from the surface of tumor cells makes...
lectins which bind asialoglycoprotein and glycoproteins from which a sialicacid has been removed to expose galactose residues. The receptors, which are...
The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle or the TCA cycle (tricarboxylic acid cycle)—is a series of biochemical reactions...
disease. Acute-phase proteins, particularly fibrinogen, interact with sialicacid on the surface of RBCs to facilitate the formation of rouleaux. An increase...
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