Asparagine

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(Redirected from Asn)

{{NatOrganicBox | image= Image:L-asparagine-skeletal.png Image:L-asparagine-3D-sticks.png | name=(2S)-2-amino-3-carbamoyl-
propanoic acid | abbreviations=N, Asn | C=4 | H=8 | N=2 | O=3 | charge= | mass=132.118 | melt_point=235 | density= | isoelectric_point=5.41 | dissoc_constant=2.16
8.73 | CAS=[70-47-3] | EINECS=200-735-9 | PubChem=6267 (L) Template:Ref N | SMILES=NC(=O)CC(N)C(=O)O }}

Asparagine is one of the 20 most common natural amino acids on Earth. It has carboxamide as the side chain's functional group. It is considered a non-essential amino acid. Asparagine was the first amino acid to be isolated. It was obtained from asparagus juice(hence the name)

Its three-letter abbreviation is Asn, and its one-letter abbreviation is N. A three-letter designation for either asparagine or aspartic acid is Asx (one-letter abbreviation: B).

A reaction between asparagine and reducing sugars or reactive carbonyls produces acrylamide (acrylic amide) in food when heated to sufficient temperature, i.e. baking. These occur primarilly in baked goods such as french fries, potato chips, and roasted coffee.

A byproduct of the breakdown of asparagine (asparagine-amino-succinic-acid monoamide) is also blamed for the smell in some people's urine after they have eaten asparagus (Some scientists disagree and implicate other substances in the smell, especially methanethiol). Asparagine was first discovered in asparagus, which has a high concentration of the amino acid. It was the first amino acid to be discovered, in 1806.

1 Biosynthesis
2 Degradation
3 Function
4 Sources
5 References
6 External links

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Biosynthesis

Asparagine is a nonessential amino acid, meaning that it can be synthesized from central metabolic pathyway intermediates in humans. The precursor to asparagine is oxaloacetate. Oxaloacetate is converted to aspartate using a transaminase enzyme. The enzyme transfers the amino group from glutamate to oxaloacetate producing α-ketoglutarate and aspartate. The enzyme asparagine synthetase produces asparagine, AMP, glutamate, and pyrophosphate from aspartate, glutamine, and ATP. In the asparagine synthetase reaction, ATP is used to activate aspartate, forming β-aspartyl-AMP. Glutamine donates an ammonium group which reacts with β-aspartyl-AMP to form asparagine and free AMP.

Image:Asn biosynthesis.gif

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Degradation

Aspartate is a glucogenic amino acid. L-asparginase hydrolyzes the amide group to form aspartate and ammonium. A transaminase converts the aspartate to oxaloacetate which can then be metabolized in the citric acid cycle or gluconeogenesis.

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Function

Nervous system needs Asparagine to maintain the equilibrium and also in amino acid transformation. It also plays an important role in the synthesis of ammonia.

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