Arginine (abbreviated as Arg or R) encoded by the codons CGU, CGC, CGA, CGG, AGA, and AGG [1] is an ɑ-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated -+NH3 form under biological conditions), an α-carboxylic acid group (which is in the deprotonated –COO- form under biological conditions), and a side chain of a 3-carbon aliphatic straight chain capped by a complex guanidinium, classifying it as a charged (at physiological pH), aliphatic amino acid. Arginine is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual.[2] Preterm infants are unable to synthesize or create arginine internally, making the amino acid nutritionally essential for them.[3] Most healthy people do not need to supplement with arginine because their body produces sufficient amounts.[4]
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Other names
2-Amino-5-guanidinopentanoic acid
|
CAS Number
|
617-45-8 56-84-8 (L-isomer) 1783-96-6 (D-isomer) |
ChEBI | CHEBI:22660 |
ChEMBL | ChEMBL139661 |
ChemSpider | 411 |
EC Number | 200-291-6 |
Jmol interactive 3D | |
KEGG | C16433 |
PubChem | 424 |
UNII | 28XF4669EP |
InChI[show]
|
|
SMILES[show]
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Chemical formula
|
C4H7NO4 |
Molar mass | 133.10 ;g·mol−1 |
Appearance | colourless crystals |
Density | 1.7 g/cm3 |
Melting point | 270 ;°C (518 ;°F; 543 ;K) |
Boiling point | 324 ;°C (615 ;°F; 597 ;K) (decomposes) |
Solubility in water
|
4.5 g/L[2] |
Acidity (pKa) | 3.9 |
Basicity (pKb) | 1.509 |
Specific
heat capacity (C) |
232.8 J K−1 mol−1 (at 23.7 °C) |
Std molar
entropy (So298) |
250.6 J K−1 mol−1 |
Std enthalpy of
formation (ΔfHo298) |
−624.9–−622.3 kJ mol−1 |
Std enthalpy of
combustion (ΔcHo298) |
−3.7396–−3.7370 MJ mol−1 |
Safety data sheet | See: data page Sigma-Aldrich |
GHS pictograms | |
GHS signal word | WARNING |
GHS hazard statements
|
H319 |
GHS precautionary statements
|
P305+351+338 |
EU classification (DSD)
|
Xi |
R-phrases | R36 |
S-phrases | S26 |
Lethal dose or concentration (LD, LC): | |
LD50 (Median dose)
|
5110 mg/kg (rat, oral) |
Related alkanoic acids
|
N-Methyl-D-aspartic acid beta-Methylamino-L-alanine Guanidinopropionic acid Theanine Pantothenic acid |
Related compounds | Pantheno |
Structure and
properties |
Refractive index (n), Dielectric constant (εr), etc. |
Thermodynamic
data |
Phase behaviour solid–liquid–gas |
Spectral data
|
UV, IR, NMR, MS |