[Synthetic tripeptides as chemotaxins or chemotaxin antagonists (author's transl)].

The possibility of changing N-terminally protected tripeptides with chemotactic activity into antagonists by variation of the protecting group was investigated. Chemotactic activity in the agarose test was shown for a series of new structurally related formylated tripeptides. The effect could be antagonised with one exception by Boc-analogues. These antagonists are very likely bound to the same membrane receptor of polymorphonuclear leucocytes as the chemotaxins. The antagonists do not influence the activity of the naturally occurring chemotaxin C5a. The syntheses of the test compounds are described.