Glycylglycine

Glycylglycine is the dipeptide of glycine, making it the simplest peptide.^[1] The compound was first synthesized by Emil Fischer and Ernest Fourneau in 1901 by boiling 2,5-diketopiperazine (glycine anhydride) with hydrochloric acid.^[2] Shaking with alkali^[1] and other synthesis methods have been reported.^[3]

Glycylglycine

Skeletal formula of glycylglycine
Names
IUPAC name Glycylglycine
Systematic IUPAC name (2-Aminoacetamido)acetic acid
Other names Diglycine Diglycocoll Glycine dipeptide Glycyl-glycine N-Glycylglycine
Identifiers
CAS Number	556-50-3 Y
3D model (JSmol)	Interactive image
Abbreviations	Gly-Gly
Beilstein Reference	1765223
ChEBI	CHEBI:17201 N
ChEMBL	ChEMBL292467 Y
ChemSpider	10690 Y
ECHA InfoCard	100.008.299
EC Number	209-127-8
Gmelin Reference	82735
KEGG	C02037 Y
MeSH	Glycylglycine
PubChem CID	11163
UNII	10525P22U0 Y
CompTox Dashboard (EPA)	DTXSID90862194
InChI InChI=1S/C4H8N2O3/c5-1-3(7)6-2-4(8)9/h1-2,5H2,(H,6,7)(H,8,9) Y Key: YMAWOPBAYDPSLA-UHFFFAOYSA-N Y
SMILES NCC(=O)NCC(O)=O
Properties
Chemical formula	C4H8N2O3
Molar mass	132.119 g·mol−1
Appearance	White crystals
Solubility in water	132 g L−1 (at 20 °C)
log P	−2.291
Acidity (pKa)	3.133
Basicity (pKb)	10.864
UV-vis (λmax)	260 nm
Absorbance	0.075
Thermochemistry
Heat capacity (C)	163.97 J K−1 mol−1
Std molar entropy (S⦵298)	180.3 J K−1 mol−1
Std enthalpy of formation (ΔfH⦵298)	−749.0 to −746.4 kJ mol−1
Std enthalpy of combustion (ΔcH⦵298)	−1.9710 to −1.9684 MJ mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H319
Precautionary statements	P305+P351+P338
Related compounds
Related alkanoic acids	Acetylcysteine Iminodiacetic acid Nitrilotriacetic acid N-Oxalylglycine Tiopronin Bucillamine Oxalyldiaminopropionic acid
Related compounds	N-Acetylglycinamide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Because of its low toxicity, it is useful as a buffer for biological systems with effective ranges between pH 2.5–3.8 and 7.5–8.9;^[4] however, it is only moderately stable for storage once dissolved.^[5] It is used in the synthesis of more complex peptides.^[6]

Glycylglycine has also been reported to be helpful in solubilizing recombinant proteins in E. coli. Using different concentrations of the glycylglycine improvement in protein solubility after cell lysis has been observed.^[7]