Diglycine

Diglycine, also known as glycylglycine, is the dipeptide formed from two glycine residues linked by a single peptide bond. Its systematic name reflects its structure, with an N-terminal amino group and a C-terminal carboxyl group: H2N-CH2-CO-NH-CH2-COOH. The chemical formula is C4H8N2O3, and its molar mass is about 132.12 g/mol.

Diglycine exists as a neutral, water-soluble compound. At physiological pH it behaves as a zwitterion, with the amino and carboxyl groups carrying charges appropriate to the surrounding pH. It is typically a colorless, crystalline solid and is stable under standard laboratory conditions.

Occurrence and synthesis: Diglycine can occur as a breakdown product of proteins during proteolysis, though it is not a major naturally abundant metabolite. It is commonly prepared synthetically via standard dipeptide coupling methods, such as carbodiimide-mediated condensation of two glycine units or via enzymatic synthesis using dipeptide-forming enzymes.

Uses: In scientific research, glycylglycine serves as a simple model dipeptide for studies of peptide bond formation and enzymatic cleavage. It is also used as a reference standard in analytical methods for amino acids and peptides and as a substrate in peptide chemistry and structural studies.

See also: Glycine, Dipeptide, Peptide bond, Glycylglycine.