Dipeptide

A dipeptide is a molecule consisting of two amino acids joined by a single peptide bond.

Dipeptides are produced from polypeptides by the action of the hydrolase enzyme dipeptidyl peptidase. Dietary proteins are digested to dipeptides and amino acids, and the dipeptides are absorbed more rapidly than the amino acids, because their uptake involves a separate mechanism. Dipeptides activate G-cells found in the stomach to secrete gastrin.

The Bergmann azlactone peptide synthesis is a classic organic synthesis for the preparation of dipeptides.

Examples of dipeptides

 * Carnosine (beta-alanyl-L-histidine) is highly concentrated in muscle and brain tissues.
 * Anserine (beta-alanyl-N-methyl histidine) is found in the skeletal muscle and brain of mammals.
 * Homoanserine (N-(4-Aminobutyryl)-L-histidine) is another dipeptide identified in the brain and muscles of mammals.
 * Kyotorphin (L-tyrosyl-L-arginine) is a neuroactive dipeptide which plays a role in pain regulation in the brain.
 * Balenine (or ophidine) (beta-alanyl-N tau-methyl histidine) has been identified in the muscles of several species of mammal (including man), and the chicken.
 * Aspartame (N-L-a-aspartyl-L-phenylalanine 1-methyl ester) is an artificial sweetener.
 * Glorin (N- propionyl-γ-L-glutamyl-L-ornithine-δ-lac ethyl ester) is a chemotactic dipeptide for the slime-mould Polysphondylium violaceum.
 * Barettin (cyclo-[(6-bromo-8-en-tryptophan)-arginine]) is a cyclic dipeptide from the marine sponge Geodia barretti.
 * Pseudoproline
 * Glycylglycine