phenylalanineglycine

Phenylalanineglycine, commonly abbreviated Phe-Gly, is a dipeptide consisting of the amino acids L-phenylalanine and glycine linked by a single peptide bond between the carboxyl group of phenylalanine and the amino group of glycine. In this dipeptide, the N-terminus is the amino group of phenylalanine, and the C-terminus is the carboxyl group of glycine. When formed by condensation, one molecule of water is removed.

Chemically, Phe-Gly combines the hydrophobic side chain of phenylalanine with the small, flexible glycine residue, giving the dipeptide a balance of hydrophobicity and conformational flexibility relative to dipeptides that contain only bulky residues. The phenyl ring in the phenylalanine moiety enables interactions with aromatic or hydrophobic environments, while glycine provides rotational freedom at the peptide bond.

Natural occurrence and use: As a dipeptide, Phe-Gly can occur as part of longer proteins produced by proteolysis. It also serves as a model dipeptide in enzyme assays and as a building block in solid-phase peptide synthesis. The properties of the dipeptide depend on the stereochemistry; the common form is L-phenylalanine-Gly.

Biological and analytical relevance: Dipeptides such as Phe-Gly are used to study dipeptidases and peptide transport mechanisms, and they illustrate the basic chemistry of peptide bonds and N- and C-terminal functionalities in short peptides.

See also: dipeptide; peptide bond; proteolysis; solid-phase peptide synthesis.