A

David

Darling

peptide

formation of a dipeptide containing one peptide bond

The peptide bond is one of the hallmarks of proteins. Here a simple reaction between two amino acids yields a dipeptide (glycyclalanine) containing one peptide bond.


A peptide is a sequence of amino acids held together by peptide bonds, in which the amino group (–NH2) of one acid links to the carboxyl group (–COOH) of another. Peptides can vary in length from dipeptides, with two amino acids (e.g., glycyclalanine, which is a combination of glycine and alanine), to polypeptides with several hundred. Polypeptides, in turn, link together to form proteins.

 


peptide bond

 

peptide bond
Formation of a peptide bond.

 

A peptide bond is the chemical linkage -CO-NH- formed by the condensation of the amino group and carboxyl group of a pair of amino acids.

 


polypeptide

A polypeptide is a molecule consisting of many amino acids joined together by peptide bonds. One or more polypeptide chains link together to form a protein.