NationMaster - Encyclopedia: Sialic acid

Sialic acid

Identifiers
CAS number	131-48-6
PubChem	445063
MeSH	Sialic+Acid
Properties
Molecular formula	C₁₁H₁₉NO₉
Molar mass	309.275
Appearance	White crystalline powder
Melting point	186°C (decomposes) Image File history File links Sialic_acid. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... PubChem is a database of chemical molecules. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Sialic acid is a generic term for the N- or O-substituted derivatives of neuraminic acid, a nine-carbon monosaccharide. It is also the name for the most common member of this group, N-acetylneuraminic acid (Neu5Ac or NANA). Sialic acids are found widely distributed in animal tissues and in bacteria, especially in glycoproteins and gangliosides. The amino group bears either an acetyl or a glycolyl group. The hydroxyl substituents may vary considerably: acetyl, lactyl, methyl, sulfate and phosphate groups have been found. The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... Neuraminic acid (5-amino-3,5-dideoxy- D-glycero-D-galacto-non-2-ulosonic acid) is a 9-carbon monosaccharide. ... For other uses, see Carbon (disambiguation). ... Monosaccharides are the simplest form of carbohydrates. ... N-acetylneuraminic acid, a sialic acid Sialic acid is a generic term for the N- or O-substituted derivatives of neuraminic acid, a nine-carbon monosaccharide. ... A glycoprotein is a macromolecule composed of a protein and a carbohydrate (an oligosaccharide). ... Ganglioside is a compound composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (AKA n-acetylneuraminic acid) linked on the sugar chain. ...

Sialic acid rich glycoproteins bind selectin in humans and other organisms. Cancer cells that can metastasize often have a lot of sialic acid rich glycoproteins. This helps these late stage cancer cells enter the blood stream. Selectins are a family of cell-surface adhesion molecules of leukocytes and endothelial cells. ...

Sialic acid-rich oligosaccharides on the glycoconjugates found on surface membranes help keep water at the surface of cells. The sialic acid-rich regions contribute to creating a negative charge on the cells surface. Since water is a polar molecule, it has a partial positive charge on both hydrogen molecules, it is attracted to cell surfaces and membranes. This also contribues to cellular fluid uptake.

Sialic acid can "hide" mannose antigens on the surface of host cells or bacteria from mannose binding lectin. This prevents activation of complement.

The term "sialic acid" (from the Greek σιαλοσ (sialos) 'saliva') was first introduced by Swedish biochemist, Gunnar Blix, in 1952.

Additional images

N-acetylneuraminic acid, a sialic acid Image File history File links N-Acetyl-neuraminsÃ¤ure2. ...

Neuraminic acid Image File history File links Metadata No higher resolution available. ... Neuraminic acid (5-amino-3,5-dideoxy- D-glycero-D-galacto-non-2-ulosonic acid) is a 9-carbon monosaccharide. ...

External link

Sialic acid in evolution
Sialic acid in UniProt knowledgebase

Categories: Carboxylic acids | Monosaccharides UniProt is the universal protein database, a central repository of protein data created by combining Swiss-Prot, TrEMBL and PIR. This makes it the worlds most comprehensive resource on protein information. ...

Results from FactBites:

Sialic Acid (241 words)
	Sialic acid is one of the small chemicals which is a component of a number of more complex chemical structures in the human body.
	A disturbance in a gene responsible for sialic acid metabolism may lead to an abnormality reflected in sialic acid concentration in blood, urine and solid tissue.
	Sialic acid can be analyzed in cells cultured from solid tissue such as skin, or can be measured in blood or urine.

Sialic acid specific slug lectin (6455 words)
	The sialic acid or sialoprotein specific lectin of the present invention is derived from the slug, Limax flavus, by homogenization of the slug tissue to release the lectin from the slug tissues with which it is associated and is partially purified by ammonium sulfate fractionation.
	The high degree of specificity of the slug lectin for sialic acid and sialoproteins enables the provision of a diagnostic method for quantitating the amount of sialic acid or sialoproteins in a biological liquid by determining its inhibitory effect on the agglutination of erythrocytes by the slug lectin.
	The acid hydrolytic release of AcNeu from glycoproteins was accomplished by incubation of the glycoprotein in 0.1N H.sub.2 SO.sub.4 at 80.degree.

More results at FactBites »

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