Dipeptides

L-α-dipeptides (dipeptides) have not been studied nearly as much has have proteins and amino acids. The primary research has been done on L-aspartyl-L-phenylalanine methylester (aspartame) and Ala-Gln (Lalanyl-L-glutamine) because they are used in popular commercial products. In addition to this fact, another reason many dipeptides have not been studied thoroughly is because dipeptide production lacks effective production processes, even though several chemical and chemoenzymatic methods have been reported.

Carnosine – example of dipeptide
Until recently, new methods have been developed for dipeptide synthesis for which dipeptides are produced via fermentative processes. Certain dipeptides have distinctive physiological capabilities, permitting them to possibly hasten dipeptide applications in various fields of scientific research. L-α-dipeptides are comprised of the most uncomplicated peptide bond of two amino acids, yet they are not readily available primarily due to the exiguity of cost-effective processes of manufacturing. Dipeptides, however, have very interesting functions, and the scientific information surrounding them is increasing. This leaves many researchers with the charge of developing more efficient and cost-effective processes of dipeptide production. When this field is more fully studied, it is anticipated that we can learn much more about how valuable peptides really are.

Dipeptides have two basic functions, which are:
1. A derivative of amino acids
2. The dipeptide itself

As a derivative of amino acids, dipeptides, along with their amino acids contain different physiochemical properties, but they usually share the same physiological effects. This is because dipeptides are degraded into the separate amino acids in living organisms, which have varying physicochemical properties. For instance, L-glutamine (Gln) is heat-labile, while the Ala-Gin (L-alanyl-L-glutamine) is heat tolerant.

Chemical synthesis of dipeptides occurs as follows:
1. All functional dipeptide groups are protected (other than those that are involved in creating the peptide bond of amino acids).
2. The protected amino acid of the free carboxyl group is activated.
3. The activated amino acid reacts with the other protected amino acid.
4. The protecting groups contained within the dipeptide become removed.