Peptidenbinding

Peptidenbinding (also known as a peptide bond or amide linkage) is the covalent chemical bond that links amino acids in peptides and proteins. It forms between the carboxyl group of one amino acid and the amino group of another through a condensation (dehydration) reaction that releases a molecule of water. In biological systems this reaction is catalyzed by the ribosome’s peptidyl transferase center during translation or by nonribosomal peptide synthetases in specialized pathways.

The peptide bond has partial double-bond character due to resonance between the carbonyl and the amide nitrogen, which makes the bond planar and limits rotation around the C–N axis. Typical bond lengths are shorter than a single C–N bond and longer than a C=N double bond, and the trans configuration is strongly favored except in certain cases such as peptide bonds preceding proline residues. These structural features influence protein secondary and tertiary structure and constrain backbone conformation.

Peptide bonds are relatively stable under physiological conditions but can be hydrolyzed by proteolytic enzymes or by chemical means under extreme pH or temperature. Synthetic peptide chemistry relies on coupling reagents and protecting-group strategies to form peptide bonds selectively; solid-phase peptide synthesis is a common laboratory method. The sequence of peptide bonds defines a protein’s primary structure and is fundamental to its folding, function, and interactions.