What is a Peptide Bond

what is a peptide bond

Peptides are amino acids, the smaller versions of proteins. Recent studies have shown the great potential of peptides in enhancing overall human health. While most people will confuse peptides with proteins, various critical features of peptides enhance their functionality. One of the key features is the peptide bond, but what is a peptide bond?

Peptide Bonds

Peptide bonds are chemical bonds found in peptides and are commonly referred to as amide bonds. These bonds connect two monomer units of a peptide, forming a polypeptide chain. Amide bonds are created through a chemical reaction involving condensation, and the water molecule is removed from the protein. Instead, the water is made by combining the NH2 and OH of one amino acid. While OH is a member of the hydroxyl group, NH2 is a hydrogen molecule from the amino group.

NH2 and OH are linked together by a dipeptide bond which is a new peptide bond. The polypeptide chains are constructed by amino acids linked together with the dipeptide bonds, forming a linear sequence. The linear sequence forms the protein’s primary structure. The process of peptide bond formation happens during protein synthesis, and the ribosomes translate the protein’s mRNA sequence coding.

Apart from being a significant part of the peptide structure, the amide bond is a covalent bond. Researchers describe the peptide bond as a rigid planar bond since it has a partial double bond character. The peptide bond’s partial double bond character features are seen from the bond’s length. The peptide bond is 0.13 Angstrom shorter than the C-N single bond, but it’s not as short as the double bonds.

The peptide bonds are broken down during a hydrolysis or amide hydrolysis process. The amide hydrolysis process is the opposite reaction to condensation. Therefore, water is added to dipeptide or polypeptide molecules breaking down the peptide bonds during the process. You will have two constituent amino acids at the end of the amide hydrolysis process.

The amide bond or peptide bond is the primary linkage between two amino acids present in a peptide. It creates a dipeptide and triggers water loss from the amino acids through condensation. One shocking fact about amide bonds is their kinetically stable nature. They can last more than 1000 years if no catalyst interferes with their stability.

When many amino acids are connected using amid bonds, they form polypeptides. Every amino molecule is referred to as a residue in a polypeptide, and the polypeptide will have a different chain end. The difference in the polypeptide chain ends is triggered by the presence of an alpha-carboxyl group on one end and the other having an alpha-amino group. Hence giving the polypeptide chain polarity capability.                              

Peptide bonds are constructed through a condensation process and broken down through an amide hydrolysis process. It is an essential part of a dipeptide and a polypeptide, connecting two or more amino acids. They are kinetically stable and can last more than 1000 years if they don’t face any interference from catalysts.