Peptide Library: Open the door to new drug candidates

Applications

• Mapping of protein-protein interaction sites: ELISA-like assays, precipitation of interacting proteins
• Antibody profiling: epitope mapping and validation, therapeutic antibody characterization, in-vitro studies of anti-antibody/neutralizing antibody action
• Identification of biomarkers: infectious and autoimmune diseases and cancer studies
• Mapping immunodominant regions in antigens: signal transduction pathways and protein fingerprinting
• Novel vaccine development: peptide vaccines, peptide drug modifications, and vaccine efficacy testing
• Enzyme profiling and motif discovery: kinases, proteases, phosphatases, methyltransferases, glycosyltransferases, proteases, and more

Screening combinatorial peptide libraries for optimal enzyme substrates and high-affinity protein ligands

The human genome project and continued improvements in peptide delivery technology have fostered many developments in the identification of novel drug targets. These have also created an increasing demand for highly effective synthetic peptide library systems.

Such peptide libraries can be used to screen enzymatic substrates, enzymatic inhibitors, and cell binding peptides. Unlike traditional techniques, combinatorial techniques handle many molecules at once. So the combinatorial chemistry has been regarded as an important tool for the discovery of new drug candidates, catalysts, and materials.

One of the important biological applications of custom peptide libraries is to characterize the binding events that occur between proteins and peptide ligands. Other applications include the identification of enzyme substrates and of the ligands that mediate cell adhesion. For example, the fluorogenic peptide substrates of proteases can be designed and used for protease substrate screening in a peptide library. Using a variety of detection methods, including surface plasmon resonance, fluorescence, and phosphorimaging, kinase activity can be quantitatively measured using a peptide library.

Peptide libraries can be used for the rapid identification of high-affinity ligands in studies of the specificity of interactions between different domains.

Phosphopeptide binding domains mediate the directed and localized assembly of protein complexes essential to intracellular kinase signaling. Peptide libraries can be used to identify phosphopeptide binding proteins. This method can be used to identify proteins that specifically bind to phosphorylated peptide library affinity matrices, including pTyr, and the motifs pSer/pThr-Pro, pSer/pThr-X-X-X-pSer/pThr, pSer/pThr-Glu/Asp, and pSer/pThr-pSer/pThr.

For example, a phosphotyrosyl (pY) peptide library containing completely randomized residues at different positions relative to the pY can be screened against biotinylated domains, and the beads that carry high-affinity ligands of the domains can be identified using an enzyme-linked assay.