noun, plural: pentapeptides
Peptides are biomolecules that are comprised of amino acids linked together by peptide bonds. The bond is formed between the carboxyl group of one amino acid and the amine group of another. A pentapeptide is a peptide comprised of five amino acids.
For example, the translation from an 18-base mRNA: 5' - AUG UUC CCC AAG GGU UGA – 3' results in the formation of a peptide with five amino acids: met – phe – pro – lys – gly *. In particular, the AUG is the codon for methionine (met) or start codon. UUC is for phenylalanine (phe). CCC is for proline (pro). AAG is for lysine (lys). GGU is for glycine (gly). UGA is a stop codon.
Example of a pentapeptide used commercially is the palmitoyl pentapeptide-4 (trademarked under the name Matrixyl). It is one of the ingredients used for making anti-wrinkle cosmetics. This compound consists of five amino acids (i.e. lysine, threonine, threonine, lysine, and serine) linked to palmitoyl. It is theorized to act as a messenger peptide that regulates cell activities, such as activating the target cell to synthesize extracellular collagen and hyaluronic acid.
Word origin: penta- (five) + peptide