Arginine

Arginine
	; Skeletal formula of arginine
Ball-and-stick model	Space-filling model
Names
	IUPAC names Arginine
	Other names 2-Amino-5-guanidinopentanoic acid
Identifiers
CAS Number	L: 74-79-3 ; D/L: 7200-25-1 ; D: 157-06-2 ; L HCl: 1119-34-2 ;
3D model (JSmol)	L: Interactive image; D: Interactive image; L HCl: Interactive image; L Zwitterion: Interactive image;
3DMet	L: B01331;
Beilstein Reference	1725411, 1725412 D, 1725413 L
ChEBI	L: CHEBI:29016 ;
ChEMBL	L: ChEMBL1485 ; D: ChEMBL212301 ;
ChemSpider	L: 6082 ; D/L: 227 ; D: 64224 ;
DrugBank	L: DB00125 ;
ECHA InfoCard	100.000.738
EC Number	L: 230-571-3;
Gmelin Reference	364938 D
IUPHAR/BPS	L: 721;
KEGG	L: C02385 ;
MeSH	Arginine
PubChem CID	L: 6322; D/L: 232; D: 71070;
RTECS number	L: CF1934200 L;
UNII	L: 94ZLA3W45F ; D/L: FL26NTK3EP ; D: R54Z304Z7C ; L HCl: F7LTH1E20Y ;
CompTox Dashboard (EPA)	L: DTXSID6041056 ;
	InChI InChI=1S/C6H14N4O2/c7-4(5(11)12)2-1-3-10-6(8)9/h4H,1-3,7H2,(H,11,12)(H4,8,9,10)/t4-/m0/s1 Key: ODKSFYDXXFIFQN-BYPYZUCNSA-N ; D/L: Key: ODKSFYDXXFIFQN-UHFFFAOYSA-N; D: Key: ODKSFYDXXFIFQN-SCSAIBSYSA-N;
	SMILES L: C(C[C@@H](C(=O)O)N)CNC(=N)N; D/L: C(CC(C(=O)O)N)CNC(=N)N; D: C(C[C@H](C(=O)O)N)CNC(=N)N; L HCl: [Cl-].NC(CCCNC(N)=[NH2+])C([O-])=O; L Zwitterion: NC(CCCNC(N)=[NH2+])C([O-])=O;
Properties
Chemical formula	C6H14N4O2
Molar mass	174.204 g·mol−1
Appearance	White crystals
Odor	Odourless
Melting point	260 °C; 500 °F; 533 K
Boiling point	368 °C (694 °F; 641 K)
Solubility in water	14.87 g/100 mL (20 °C)
Solubility	slightly soluble in ethanol; insoluble in ethyl ether
log P	−1.652
Acidity (pKa)	2.18 (carboxyl), 9.09 (amino), 13.8 (guanidino)
Thermochemistry
Heat capacity (C)	232.8 J K−1 mol−1 (at 23.7 °C)
Std molar; entropy (S⦵298)	250.6 J K−1 mol−1
Std enthalpy of; formation (ΔfH⦵298)	−624.9–−622.3 kJ mol−1
Std enthalpy of; combustion (ΔcH⦵298)	−3.7396–−3.7370 MJ mol−1
Pharmacology
ATC code	B05XB01 (WHO) S
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H319
Precautionary statements	P305+P351+P338
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	5110 mg/kg (rat, oral)
Safety data sheet (SDS)	L-Arginine
Related compounds
Related alkanoic acids	N-Methyl-D-aspartic acid; beta-Methylamino-L-alanine; Guanidinopropionic acid; Theanine; Pantothenic acid;
Related compounds	Panthenol;
Supplementary data page
	Arginine (data page)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Arginine is the amino acid with the formula (H₂N)(HN)CN(H)(CH₂)₃CH(NH₂)CO₂H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO₂⁻) and both the amino and guanidino groups are protonated, resulting in a cation. Only the l-arginine (symbol Arg or R) enantiomer is found naturally.^[1] Arg residues are common components of proteins. It is encoded by the codons CGU, CGC, CGA, CGG, AGA, and AGG.^[2] The guanidine group in arginine is the precursor for the biosynthesis of nitric oxide.^[3] Like all amino acids, it is a white, water-soluble solid.

The one-letter symbol R was assigned to arginine for its phonetic similarity.^[4]

^ "Nomenclature and Symbolism for Amino Acids and Peptides". IUPAC-IUB Joint Commission on Biochemical Nomenclature. 1983. Archived from the original on 9 October 2008. Retrieved 5 March 2018.
^ IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. "Nomenclature and Symbolism for Amino Acids and Peptides". Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc. Archived from the original on 29 May 2007. Retrieved 2007-05-17.
^ Ignarro LJ (2000-09-13). Nitric Oxide: Biology and Pathobiology. Academic Press. p. 189. ISBN 978-0-08-052503-7.
^ "IUPAC-IUB Commission on Biochemical Nomenclature A One-Letter Notation for Amino Acid Sequences". Journal of Biological Chemistry. 243 (13): 3557–3559. 10 July 1968. doi:10.1016/S0021-9258(19)34176-6.

[1] "Nomenclature and Symbolism for Amino Acids and Peptides". IUPAC-IUB Joint Commission on Biochemical Nomenclature. 1983. Archived from the original on 9 October 2008. Retrieved 5 March 2018.

[2] IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. "Nomenclature and Symbolism for Amino Acids and Peptides". Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc. Archived from the original on 29 May 2007. Retrieved 2007-05-17.

[:0-3] Ignarro LJ (2000-09-13). Nitric Oxide: Biology and Pathobiology. Academic Press. p. 189. ISBN 978-0-08-052503-7.

[:02-4] "IUPAC-IUB Commission on Biochemical Nomenclature A One-Letter Notation for Amino Acid Sequences". Journal of Biological Chemistry. 243 (13): 3557–3559. 10 July 1968. doi:10.1016/S0021-9258(19)34176-6.

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