Rapid developments in the biotechnology of new proteins, as well as advances in immunology and the development of pharmaceuticals based on inhibitors and antagonists, have led to immense demands for synthetic peptides. Simultaneous preparation of 100–150 completely different peptides, having chain lengths of up to 20 amino acids can nowadays be achieved using multiple synthesis methods. The yields and qualities of the peptides so obtained are high enough to permit reliable in vivo and in vitro screening for biological activities. Moreover, it is possible to optimize synthetic conditions and to carry out comparative studies on the secondary structures and conformational mapping of proteins. Special multiple synthesis methods facilitate the epitope mapping of larger peptides for diagnostic purposes and for the development of vaccines based on a few hundreds of free or rod‐bound peptides that are useful for immunoassays. Multiple methods of peptide synthesis also enable the preparation of so‐called peptide libraries which could comprise hundreds of thousands of peptides, and by which new perspectives for the screening of lead structures will be opened up. Peptide synthesis using a combination of photolabile protecting groups and photolithographic procedures enables the assembling of peptide libraries on small plates for use in miniature immunoassays. Furthermore, lipopeptide‐antigen conjugates allow both the preparation of peptide‐specific and monoclonal antibodies as well as a complete screening of epitopes of B‐, T‐helper and T‐killer cells. Applications in the areas of AIDS diagnosis, the development of vaccines, and screening for the hormone analogues, demonstrate just some of the possibilities that have been opened up by multiple peptide synthesis methods.

Peptide fishing is a new sport in bioorganic and medicinal chemistry–biologically active peptides are identified from an ocean of peptides of various lengths and constitutions. In the last few years new methods have been developed for the synthesis of such peptide collections. Automation is the next step. For example, in immuno‐analysis the pin method is very important. Minute amounts of peptide are synthesized on rods (a few hundred simultaneously) and incubated with sera containing antibodies for the analysis. In this way the relevant epitopes, that is, the regions to which the antibodies bind, can be precisely determined and mapped.