Protein and Peptide Sciences

The field of proteins and peptides is extremely important to drug design and discovery. First of all, most targets for drug discovery are proteins; these include enzymes and receptors. Successful drug discovery efforts must be supported by the production of these proteins for activity assays, ligand-protein interaction analyses, NMR and co-crystallization trials for structural analysis. Second, many proteins are also drugs or potential drugs; insulin is considered either a peptide or a small protein, cytokines and other cellular regulators are also proteins, and new proteins have been discovered to have significant biological activity that mark them as potential drugs.
In addition to insulin, many peptides are now known as drugs, including antimicrobial defensins, various peptide hormones, and neurotoxins, which can be used to probe membrane channels. Peptides can be prepared either by recombinant expression in bacteria or other hosts, as well as by chemical synthesis. The latter method provides the opportunity to create variants with altered properties and this can also produce new drug entities. A simple example is the design and production of peptide analogs that have agonist or antagonist activities against membrane-embedded hormone receptors. Chemical synthesis expands considerably the molecular diversity of peptides by incorporating non-natural amino acids and analogs of amino acids.