Sialic acid

sialic acidssialylationsialylatedsialicdesialatedsialic acid biosynthetic pathwaysialic acid residuessialyl
Sialic acid is a generic term for a family of derivatives of neuraminic acid, an acidic sugar with a nine-carbon backbone.wikipedia
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N-Acetylneuraminic acid

N-acetylneuraminateN''-acetylneuraminic acidNeu5Ac
It is also the name for the most common member of this group, N-acetylneuraminic acid (Neu5Ac or NANA).
N-Acetylneuraminic acid (Neu5Ac or NANA) is the predominant sialic acid found in human cells, and many mammalian cells.

Ganglioside

gangliosidesdisialoganglioside
Sialic acids are found widely distributed in animal tissues and to a lesser extent in other organisms, ranging from fungi to yeasts and bacteria, mostly in glycoproteins and gangliosides (they occur at the end of sugar chains connected to the surfaces of cells and soluble proteins).
A ganglioside is a molecule composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (e.g. n-acetylneuraminic acid, NANA) linked on the sugar chain.

Neuraminic acid

Aminononulosonic acidneuraminic acids
Sialic acid is a generic term for a family of derivatives of neuraminic acid, an acidic sugar with a nine-carbon backbone.
The N- or O-substituted derivatives of neuraminic acid are collectively known as sialic acids, the predominant form in mammalian cells being N-acetylneuraminic acid.

Glycoprotein

glycoproteinsmembrane glycoproteinprotein
Sialic acids are found widely distributed in animal tissues and to a lesser extent in other organisms, ranging from fungi to yeasts and bacteria, mostly in glycoproteins and gangliosides (they occur at the end of sugar chains connected to the surfaces of cells and soluble proteins). Normally they can be found as components of oligosaccharide chains of mucins, glycoproteins and glycolipids occupying terminal, nonreducing positions of complex carbohydrates on both external and internal membrane areas where they are very exposed and develop important functions.

Sialoglycoprotein

sialoglycoproteins
Sialic acid-rich glycoproteins (sialoglycoproteins) bind selectin in humans and other organisms.
A sialoglycoprotein is a combination of sialic acid and glycoprotein, which is, itself, a combination of sugar and protein.

Fructose-bisphosphate aldolase

aldolasealdehyde lyasesEC 4.1.2.13
In bacterial systems, sialic acids are biosynthesized by an aldolase enzyme.
The word aldolase also refers, more generally, to an enzyme that performs an aldol reaction (creating an aldol) or its reverse (cleaving an aldol), such as Sialic acid aldolase, which forms sialic acid.

Glycolipid

glycolipidsglyceroglycolipid
Normally they can be found as components of oligosaccharide chains of mucins, glycoproteins and glycolipids occupying terminal, nonreducing positions of complex carbohydrates on both external and internal membrane areas where they are very exposed and develop important functions.

Gunnar Blix

The term "sialic acid" (from the Greek for saliva, - síalon) was first introduced by Swedish biochemist Gunnar Blix in 1952.
He discovered and named sialic acids in 1952.

Lipopolysaccharide

endotoxinLPSlipopolysaccharides
Many of these incorporate sialic acid into cell surface features like their lipopolysaccharide and capsule, which helps them evade the innate immune response of the host.
Additionally, Neisseria gonorrhoeae, as well as Neisseria meningitidis and Haemophilus influenzae, are capable of further modifying their LOS in vitro, for example through sialylation (modification with sialic acid residues), and as a result are able to increase their resistance to complement-mediated killing or even down-regulate complement activation or evade the effects of bactericidal antibodies.

Adenoviridae

adenovirusadenovirusesadenoviral
Many viruses such as some adenoviruses (Adenoviridae), rotaviruses (Reoviridae) and influenza viruses (Orthomyxoviridae) can use host-sialylated structures for binding to their target host cell.
There are some reports suggesting MHC molecules and sialic acid residues functioning in this capacity as well.

Neuraminidase

N2exo-a-sialidaseN
Widely used anti-influenza drugs (oseltamivir and zanamivir) are sialic acid analogs that interfere with release of newly generated viruses from infected cells by inhibiting the viral enzyme neuraminidase.
Neuraminidases, also called sialidases, catalyze the hydrolysis of terminal sialic acid residues from the newly formed virions and from the host cell receptors.

Sialidase

The sialidase is one of the most important enzymes of the sialic acid catabolism.
Sialidases hydrolyse alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)-glycosidic linkages of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates.

Sialyltransferase

glycosyltransferase family 29sialyltransferases
Sialyltransferases are enzymes that transfer sialic acid to nascent oligosaccharide.

Red blood cell

red blood cellserythrocyteserythroid
The influenza viruses have hemagglutinin activity (HA) glycoproteins on their surfaces that bind to sialic acids found on the surface of human erythrocytes and on the cell membranes of the upper respiratory tract.
Much of this potential appears to be contributed by the exposed sialic acid residues in the membrane: their removal results in zeta potential of −6.06 mV.

Influenza A virus

influenza AInfluenzavirus Abird flu
All influenza A virus strains need sialic acid to connect with cells.

Oseltamivir

TamifluFluviroseltamavir
Widely used anti-influenza drugs (oseltamivir and zanamivir) are sialic acid analogs that interfere with release of newly generated viruses from infected cells by inhibiting the viral enzyme neuraminidase.
The enzyme cleaves the sialic acid which is found on glycoproteins on the surface of human cells that helps new virions to exit the cell.

Reoviridae

reovirusdouble-stranded RNAREO virus
Many viruses such as some adenoviruses (Adenoviridae), rotaviruses (Reoviridae) and influenza viruses (Orthomyxoviridae) can use host-sialylated structures for binding to their target host cell.
The receptor is not known but is thought to include sialic acid and junctional adhesion molecules (JAMs).

Orthomyxoviridae

influenza virusinfluenza virusesflu virus
Many viruses such as some adenoviruses (Adenoviridae), rotaviruses (Reoviridae) and influenza viruses (Orthomyxoviridae) can use host-sialylated structures for binding to their target host cell.
The viruses bind to a cell through interactions between its hemagglutinin glycoprotein and sialic acid sugars on the surfaces of epithelial cells in the lung and throat (Stage 1 in infection figure).

Zanamivir

Relenza
Widely used anti-influenza drugs (oseltamivir and zanamivir) are sialic acid analogs that interfere with release of newly generated viruses from infected cells by inhibiting the viral enzyme neuraminidase.
It was also known, as far back as 1974, that 2-deoxy-2,3-didehydro-N-acetylneuraminic acid (DANA), a sialic acid analogue, is an inhibitor of neuraminidase.

Salla disease

sialic acid storage diseaseSialuria, Finnish type
Salla disease is an extremely rare illness which is considered the mildest form of the free sialic acid accumulation disorders though its childhood form is considered an aggressive variant and people who suffer from it have mental retardation.
The mutation causes sialic acid to build up in the cells.

Sialidosis

mucolipidosis IMucolipidosis type 1neuraminidase
Sialidosis would be an example of this type of disorder.
The role of sialidase is to remove a particular form of sialic acid (a sugar molecule) from sugar-protein complexes (referred to as glycoproteins), which allows the cell to function properly.

Sugar acid

acidicacidic sugarSugar acids
Sialic acid is a generic term for a family of derivatives of neuraminic acid, an acidic sugar with a nine-carbon backbone.

Carbon

Ccarbonaceouscarbon atom
Sialic acid is a generic term for a family of derivatives of neuraminic acid, an acidic sugar with a nine-carbon backbone.

Synaptogenesis

synapse formationform new synapsesformation of synapses
In humans the brain has the highest sialic acid concentration, where these acids play an important role in neural transmission and ganglioside structure in synaptogenesis.

Regulation of gene expression

gene regulationregulationregulatory
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.