Peptide bonds are the bonds responsible for holding amino acids together during the formation of peptides. The number of bonds in each molecule determines the length, as well as the complexity of the peptide.
The bonds are formed when more than two amino groups come together, displacing a molecule of water in the process. The amino acids are then bound together by covalent peptide bonds, which are extremely strong, and in addition to holding the molecules together, they also bind any material that might be present between the bonds. The bonds are sometimes known as amide bonds.
Classification of peptide bonds
The classification of peptide bonds is dependent upon the total number of the molecules that constitutes the chain. Consequently, some of the classifications we have included are as follows:
- Dipeptide bonds – bonds between two amino acids
- Tripeptide bonds – bonds between three amino acids
- Tetrapeptide bonds – bonds between four amino acids
- Oligopeptide bonds – bonds between peptides with more than ten amino acids
- Macropeptide bonds – bonds between peptides with more than 100 amino acids
Common features of the peptide bonds
Some of the features you will find common to the peptide bonds include:
- Peptide bonds are rigid and appear to exhibit the planar structure.
- The bonds are coplanar to suggest that they share two electrons between the carboxyl oxygen, and the amide nitrogen. Partial double bond characters can also be seen in their structure.
- The atoms that make up the peptide bonds align themselves in a singular plane in a manner that the hydrogen and the oxygen atom from the amide and the carboxyl groups respectively appear to be trans to one another.
Characteristics of the bonds
The main characteristic of such peptide bonds, is that they are rigid and planar and also feature partial bond characteristics. Additionally, both the amide end and the carboxyl end contribute to the formation of the hydrogen bond.