There are two main methods for peptide library synthesis: monomer method and sub monomer method.
Monomer method
Monomer method is a traditional approach for peptide library synthesis. In this method, all protected monomers need to be synthesized first, and the synthesis process of each protected monomer is cumbersome and time-consuming.
Secondary monomer method
The secondary monomer method does not require monomers with protected alpha amino groups. This method consists of two steps: nucleophilic substitution followed by acylation. The sub monomer method allows the use of any commercially available or synthetically available amine, with great potential for combinatorial chemistry.