Asparagine

L-Asparagine

Names
IUPAC name Asparagine
Other names 2-Amino-3-carbamoylpropanoic acid
Identifiers
CAS Number	70-47-3 Y
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:17196 Y
ChEMBL	ChEMBL58832 Y
ChemSpider	6031 Y
DrugBank	DB03943 Y
ECHA InfoCard	100.000.669
EC Number	200-735-9
IUPHAR/BPS	4533
KEGG	C00152 Y
PubChem	236
UNII	7NG0A2TUHQ Y
InChI InChI=1S/C4H8N2O3/c5-2(4(8)9)1-3(6)7/h2H,1,5H2,(H2,6,7)(H,8,9)/t2-/m0/s1 Y Key: DCXYFEDJOCDNAF-REOHCLBHSA-N Y InChI=1/C4H8N2O3/c5-2(4(8)9)1-3(6)7/h2H,1,5H2,(H2,6,7)(H,8,9)/t2-/m0/s1 Key: DCXYFEDJOCDNAF-REOHCLBHBD
SMILES O=C(N)C[C@H](N)C(=O)O C([C@@H](C(=O)O)N)C(=O)N
Properties
Chemical formula	C4H8N2O3
Molar mass	132.12 g·mol−1
Appearance	white crystals
Density	1.543 g/cm3
Melting point	234 °C (453 °F; 507 K)
Boiling point	438 °C (820 °F; 711 K)
Solubility in water	2.94 g/100 mL
Solubility	soluble in acids, bases, negligible in methanol, ethanol, ether, benzene
log P	−3.82
Acidity (pKa)	2.02 (carboxyl), 8.80 (amino)
Magnetic susceptibility (χ)	-69.5·10−6 cm3/mol
Structure
Crystal structure	orthorhomic
Thermochemistry
Std enthalpy of formation (ΔfHo298)	−789.4 kJ/mol
Hazards
Safety data sheet	See: data page Sigma-Alrich
NFPA 704	0 1 0
Flash point	219 °C (426 °F; 492 K)
Supplementary data page
Structure and properties	Refractive index (n), Dielectric constant (εr), etc.
Thermodynamic data	Phase behaviour solid–liquid–gas
Spectral data	UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Asparagine (abbreviated as Asn or N), encoded by the codons AAU and AAC, is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+
3 form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO⁻ form under biological conditions), and a side chain carboxamide, classifying it as a polar (at physiological pH), aliphatic amino acid. It is non-essential in humans, meaning the body can synthesize it. A reaction between asparagine and reducing sugars or other source of carbonyls produces acrylamide in food when heated to sufficient temperature. These products occur in baked goods such as French fries, potato chips, and toasted bread.

Asparagine was first isolated in 1806 in a crystalline form by French chemists Louis Nicolas Vauquelin and Pierre Jean Robiquet (then a young assistant) from asparagus juice, in which it is abundant, hence the chosen name. It was the first amino acid to be isolated.

Three years later, in 1809, Pierre Jean Robiquet identified a substance from liquorice root with properties he qualified as very similar to those of asparagine, and that Plisson identified in 1828 as asparagine itself.

Since the asparagine side-chain can form hydrogen bond interactions with the peptide backbone, asparagine residues are often found near the beginning of alpha-helices as asx turns and asx motifs, and in similar turn motifs, or as amide rings, in beta sheets. Its role can be thought as "capping" the hydrogen bond interactions that would otherwise be satisfied by the polypeptide backbone. Glutamines, with an extra methylene group, have more conformational entropy and thus are less useful for capping.