Peptide Bond
A peptide bond is the covalent chemical bond formed between the carboxyl group of one amino acid and the amine group of another, releasing a water molecule in the process. It is the linkage that holds peptide and protein chains together.
Overview
Peptide bond formation is a condensation reaction: when two amino acids are linked, the hydroxyl group of one's carboxyl and the hydrogen of the other's amine are released as water. The resulting C–N bond has partial double-bond character, which restricts rotation and gives the peptide backbone a planar geometry. This rigidity influences how peptide chains fold in three-dimensional space. Peptide bonds are relatively stable at neutral pH but can be broken (hydrolyzed) by water — a reaction accelerated by acid, base, or proteolytic enzymes. This susceptibility to hydrolysis is why storing reconstituted peptides at refrigerator temperatures (2–8°C) is important for maintaining potency.
Related Terms
Frequently asked questions
Can peptide bonds be broken naturally in the body?+
Yes. Protease enzymes break peptide bonds as part of normal protein digestion and peptide metabolism. This is why most peptides degrade in the digestive tract when taken orally.
What is the difference between a peptide bond and a disulfide bond?+
A peptide bond links amino acids within the chain backbone. A disulfide bond is a different type of bond formed between the sulfur atoms of two cysteine residues, often holding parts of the folded structure together.
How does peptide bond stability affect storage?+
In dry (lyophilized) form, peptide bonds are very stable and peptides can last 12–24 months. Once reconstituted in aqueous solution, slow hydrolysis begins; refrigeration slows this process.