Glycine

Glycine
Skeletal formula of neutral glycine	Skeletal formula of zwitterionic glycine
Ball-and-stick model of the gas-phase structure	Ball-and-stick model of the zwitterionic solid-state structure
Space-filling model of the gas-phase structure	Space-filling model of the zwitterionic solid-state structure
Names
	IUPAC name Glycine
	Systematic IUPAC name Aminoacetic acid
	Other names 2-Aminoethanoic acid; Glycocol; Glycic acid; Dicarbamic acid;
Identifiers
CAS Number	56-40-6 ; 6000-43-7 (HCl salt) ;
3D model (JSmol)	Interactive image; Zwitterion: Interactive image; Interactive image;
Abbreviations	Gly, G
ChEBI	CHEBI:15428 ;
ChEMBL	ChEMBL773 ;
ChemSpider	730 ; 20944;
DrugBank	DB00145 ;
ECHA InfoCard	100.000.248
EC Number	200-272-2; 227-841-8;
E number	E640 (flavour enhancer)
IUPHAR/BPS	727;
KEGG	D00011 ;
PubChem CID	750; 22316;
UNII	TE7660XO1C ; 225ZLC74HX ;
CompTox Dashboard (EPA)	DTXSID9020667 ;
	InChI InChI=1S/C2H5NH2/c3-1-2(4)5/h1,3H2,(H,4,5) Key: DHMQDGOQFOQNFH-UHFFFAOYSA-N ; InChI=1S/C2H5NO2/c3-1-2(4)5/h1,3H2,(H,4,5) Key: DHMQDGOQFOQNFH-UHFFFAOYAW;
	SMILES C(C(=O)O)N; Zwitterion: C(C(=O)[O-])[NH3+]; C(C(=O)O)N.Cl;
Properties
Chemical formula	C2H5NO2
Molar mass	75.067 g·mol−1
Appearance	White solid
Density	1.1607 g/cm3
Melting point	233 °C (451 °F; 506 K) (decomposition)
Solubility in water	249.9 g/L (25 °C)
Solubility	soluble in pyridine ; sparingly soluble in ethanol ; insoluble in ether
Acidity (pKa)	2.34 (carboxyl), 9.6 (amino)
Magnetic susceptibility (χ)	−40.3·10−6 cm3/mol
Pharmacology
ATC code	B05CX03 (WHO)
Hazards
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	2600 mg/kg (mouse, oral)
Supplementary data page
	Glycine (data page)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Glycine (symbol Gly or G; /ˈɡlaɪsiːn/ ^ⓘ) is an organic compound with the formula C₂H₅NO₂, and is the simplest stable amino acid, distinguished by having a single hydrogen atom as its side chain. As one of the 20 proteinogenic amino acids, glycine is a fundamental building block of proteins in all life and is encoded by all codons starting with GG (GGU, GGC, GGA, and GGG). Because of its minimal side chain, it is the only common amino acid that is not chiral, meaning it is superimposable on its mirror image.

In the body, glycine plays several crucial roles. Its small and flexible structure is vital for the formation of certain protein structures, most notably in collagen, where glycine makes up about 35% of the amino acid content and enables the tight coiling of the collagen triple helix. Glycine disrupts the formation of alpha-helices in secondary protein structure, in favor instead of random coils. Beyond its structural role, glycine functions as an inhibitory neurotransmitter in the central nervous system, particularly in the spinal cord and brainstem, where it helps regulate motor and sensory signals. Disruption of glycine signaling can lead to severe neurological disorders and motor dysfunction; for example, the tetanus toxin causes spastic paralysis by blocking glycine release. It also serves as a key precursor for the synthesis of other important biomolecules, including the porphyrins that form heme in blood and the purines used to build DNA and RNA.

Glycine is a white, sweet-tasting crystalline solid, leading to its name from Greek word glykys (Greek: γλυκύς) or "sweet". While the body can synthesize it, it is also obtained from the diet and produced industrially by chemical synthesis for use as a food additive, a nutritional supplement, and an intermediate in the manufacture of products such as the herbicide glyphosate. In aqueous solutions, glycine exists predominantly as a zwitterion (H₃N⁺CH₂COO⁻), a polar molecule with both a positive and negative charge, making it highly soluble in water. It can also fit into hydrophobic environment due to its minimal side chain.