Asparagine

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Asparagine

Asparagine (abbreviated as Asn or N; Asx or B represent either asparagine or aspartic acid

Aspartic acid

Aspartic acid is an a-amino acid with the chemical formula HO2CCHCH2CO2H. The carboxylate anion of aspartic acid is known as aspartate....
) is one of the 20 most common natural amino acid

Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
s on Earth

Earth

Earth is the third planet from the Sun. Earth is the largest of the terrestrial planets in the Solar System in diameter, mass and density. It is also referred to as the World and Wiktionary:Terra.Note that by International Astronomical Union convention, the term "Terra" is used for naming extensive land masses, rather...
. It has carboxamide

Carboxamide

Carboxamides are medication that can be used as anticonvulsants. In organic chemistry carboxamides are functional groups with the general structure R-CO-NH2 with R as an organic substituent....
as the side chain

Side chain

A side chain in organic chemistry and biochemistry is a part of a molecule that is attached to a core structure. The placeholder R is often used as a generic placeholder for side chains, the R historically being derived from radical or rest....
's functional group

Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules....
. It is not an essential amino acid

Essential amino acid

File:BakedFish.jpgAn essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo synthesis by the organism , and therefore must be supplied in the diet....
. Its codons are AAU and AAC.

A reaction between asparagine and reducing sugar

Reducing sugar

A reducing sugar is any sugar that, in basic solution, forms some aldehyde or ketone. This allows the sugar to act as a reducing agent, for example in the Maillard reaction and Benedict's reagent....
s or reactive carbonyl

Carbonyl

In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double bond to an oxygen atom : C=O.The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex ; in this situation, carbon is triple-bonded to oxygen : C=O....
s produces acrylamide

Acrylamide

The chemical compound acrylamide has the chemical formula Carbon3Hydrogen5NitrogenOxygen. Its IUPAC name is 2-propenamide....
(acrylic amide) in food when heated to sufficient temperature. These products occur in baked goods such as french fries, potato chips, and roasted coffee.

ragine was first isolated in 1806 from asparagus

Asparagus

Asparagus officinalis is a flowering plant species in the genus Asparagus from which the vegetable known as asparagus is obtained....
juice, in which it is abundant -- hence its name -- becoming the first amino acid to be isolated.

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Encyclopedia

Asparagine (abbreviated as Asn or N; Asx or B represent either asparagine or aspartic acid

Aspartic acid

Aspartic acid is an a-amino acid with the chemical formula HO2CCHCH2CO2H. The carboxylate anion of aspartic acid is known as aspartate....
) is one of the 20 most common natural amino acid

Amino acid

Earth

Carboxamide

Side chain

Functional group

Essential amino acid

Reducing sugar

Carbonyl

Acrylamide

History

Asparagine was first isolated in 1806 from asparagus

Asparagus

Urine

Urine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra....
of individuals after their consumption of asparagus

Asparagus

Asparagus officinalis is a flowering plant species in the genus Asparagus from which the vegetable known as asparagus is obtained....
is attributed to various metabolic byproducts of asparagine.

Structural function in proteins

Since the asparagine side chain can form hydrogen bond interactions with the peptide backbone, asparagine residues are often found near the beginning and the end of alpha-helices, and in turn motifs in beta sheets. Its role can be thought as "capping" the hydrogen bond interactions which would otherwise be satisfied by the polypeptide backbone. Glutamine

Glutamine

Glutamine is one of the 20 amino acids encoded by the standard genetic code. Its side chain is an amide formed by replacing the side-chain hydroxyl of glutamic acid with an amine functional group....
s, with an extra methylene group, have more conformational entropy and thus are less useful in this regard.

Asparagine also provides key sites for N-linked glycosylation

Glycosylation

Glycosylation is the enzymatic process that links saccharides to produce glycans, either free or attached to proteins and lipids. This enzymatic process produces one of four fundamental components of all cells and also provides a co-translational and post-translational modification mechanism that modulates the structure and function of membr...
, modification of the protein chain with the addition of carbohydrate chains.

Sources

Dietary Sources

Asparagine is not an essential amino acid

Essential amino acid

File:BakedFish.jpgAn essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo synthesis by the organism , and therefore must be supplied in the diet....
, which means that it can be synthesized from central metabolic pathway intermediates in humans and is not required in the diet. Asparagine is found in:

Animal sources: dairy, whey, beef, poultry, eggs, fish, lactalbumin, seafood
Plant sources: asparagus, potatoes, legumes, nuts, seeds, soy, whole grains

Biosynthesis

The precursor to asparagine is oxaloacetate. Oxaloacetate is converted to aspartate using a transaminase

Transaminase

In biochemistry, a transaminase or an aminotransferase is an enzyme that catalyzes a type of reaction between an amino acid and an alpha-keto acid....
enzyme. The enzyme transfers the amino group from glutamate to oxaloacetate producing a-ketoglutarate and aspartate. The enzyme asparagine synthetase

Asparagine synthetase

Asparagine synthetase is an enzyme that generates asparagine from aspartate.External links...
produces asparagine, AMP

Adenosine monophosphate

Adenosine monophosphate , also known as 5'-adenylic acid, is a nucleotide that is found in RNA. It is an ester of phosphoric acid and the nucleoside adenosine....
, glutamate, and pyrophosphate

Pyrophosphate

In chemistry, the anion, the salts, and the esters of pyrophosphoric acid are called pyrophosphates. Pyrophosphates were originally prepared by heating phosphates: the prefix pyro- derived from Greek, means "fire" in this context....
from aspartate, glutamine

Glutamine

Adenosine triphosphate

This article is about the chemical used by cells as an energy carrier. For other uses, see ATP .Adenosine-5'-triphosphate is a multifunctional nucleotide, and plays an important role in cell biology as a coenzyme that is the "molecule unit of currency" of intracellular energy transfer....
. In the asparagine synthetase reaction, ATP is used to activate aspartate, forming ß-aspartyl-AMP. Glutamine

Glutamine

Glutamine is one of the 20 amino acids encoded by the standard genetic code. Its side chain is an amide formed by replacing the side-chain hydroxyl of glutamic acid with an amine functional group....
donates an ammonium group which reacts with ß-aspartyl-AMP to form asparagine and free AMP.

Degradation

Aspartate is a glucogenic amino acid. L-asparaginase 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

Citric acid cycle

The citric acid cycle ? also known as the tricarboxylic acid cycle ; the Krebs cycle; or, more rarely, the Szent-Gy?rgyi-Krebs cycle) ? is a series of enzyme-catalysed chemical reactions of central importance in all living cell s that use oxygen as part of cellular respiration....
or gluconeogenesis

Gluconeogenesis

Gluconeogenesis is a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as lactic acid, glycerol, and glucogenic amino acids....
.

Function

The nervous system requires asparagine. It also plays an important role in the synthesis of ammonia.