A modularly built bisubstrateinhibitor, the natural product pepticinnamin E (shown on the right) was sythesized for the first time. In the case of in vitro assays it inhibits the enzyme farnesyltransferase with respect to both the peptide substrate and farnesylpyrophosphate (KI = 30 and 8 μM, respectively). The inhibitoryactivity is decisively influenced by the central tripeptide unit and the absolute