Peptides are short chains of biologically occurring amino acid monomers that are linked by peptide bonds. Carboxyl group of one amino acid will react with amine group of another in order to form the covalent chemical bonds. 2 amino acids are joined by a single bond of peptide to form the shortest peptides.
The long and continuous peptide chain that is un-branched is called a polypeptide. Peptides therefore fall under broad chemical classes of biological polymers and oligomers alongside the oligosaccharides, nucleic acids and polysaccharides.
Peptides are differentiated from proteins basing on the size although there are cases where by long pep have been referred to as proteins and smaller proteins have been referred to as peptid. Amino acids incorporated into peptides are referred to as residues because of the release of either hydroxyl ion from carboxyl end or the release of hydrogen ion from the amine end or both.
Depending on how they are produced, peptides are divided into the following classes;
- Non ribosomal
- Peptide fragments
The prominence of the peptides in the molecular biology was achieved due to several reasons. The first reason is that peptides allow creation of the peptide antibodies in the animals with no need to purify the proteins of interest. Another reason is that peptid allow the identification of proteins of interest based on their masses and sequence.
Peptides are very useful and they have been used in the study of the structure of proteins and the function as well. Synthetic peptides for instance can be used as probes to see where there is an occurrence in the protein-peptide occurrence. Inhibitory peptides have been widely used in the clinical research in order to examine effects of peptides on inhibition of cancer.