Can peptides be mimicked?

The biological activity of peptides is of enormous interest to the pharmaceutical industry, but endogenous peptides themselves typically have some limitations regarding bioavailability and oral activity. Peptide mimicry by design used to be touted as a solution to these problems and was focused on impersonating secondary structural motifs, particularly beta-turns, but this approach has yielded few pharmaceutical products. Today, the process of identifying and optimizing peptide mimics is driven mainly by screening to obtain hits, followed by optimization, which might include design based on arranging pharmacophores appropriately in three dimensions. A consequence of this is that one of the more difficult problems in drug discovery, namely the identification of non-peptide agonists at peptide receptors, is beginning to be solved.