[Peptide chemistry today].

Peptide chemistry has reached a plateau on which more work is devoted to the improvement of known basic principles than to the development of really new methods. As a consequence, routine syntheses of peptides concentrate on few protecting groups and coupling procedures only. The recent progress in purification of peptides by liquid chromatography helped to promote this trend. Meanwhile, recombinant technology permits the synthesis of proteins and possibly of some lower peptides, too. It cannot compete, however, with chemical solid-phase synthesis of a newly discovered peptide with up to about 40 amino acids in speed but may take over the synthesis for large-scale production. Peptides containing modified or non-natural structures, which are often superior to the natural compounds as drugs, will remain subject of chemical synthesis, too. Present research focuses on the role of peptide and protein factors in the immune response and on structure and biological activities of neuropeptides.