The combinatorial peptide library is a powerful tool in which a huge number of diverse peptides are produced. It is widely used in drug discovery and development, epitope mapping, target validation, structure-activity studies.
This method has been successfully used to identify biologically active peptides, including antibacterial peptides, ligands for cell surface receptors, opioid receptor antagonists, protein kinase inhibitors and substrates.
The first use of combinatorial peptide library (96 peptides) was reported by Geysen and colleagues in 1984. The peptide library was generated with the multipin technology. Since then several different methods of synthesizing and screening peptide libraries have been developed.
Currently, there are five main approaches in peptide library methods:
1) the biologic peptide library method such as phage-display peptide library
2) the spatially addressable parallel library method
3) the combinatorial library method that requires deconvolution
4) the one-bead one-compound (OBOC) combinatorial library method
5) the synthetic library method that requires chromatography selection
Each peptide library method has its own advantages and disadvantages. The phage-display peptide library method is simple and economical. It can provide a large number of peptide entities to be screened (106-108) and fewer restrictions exist in the length of peptides that can be achieved. However, this biologic approach generally is limited to peptides that contain only 20 natural L-amino acids. The synthetic methods (2-5) can use D-amino acids, unnatural amino acids, nucleotides, monosaccharides, lipids and small organic moieties, which makes these approaches highly versatile.
The peptide library methods offer great potential for facilitating the drug discovery and development process and also provide a powerful tool for basic research.