The present invention provides peptides as inhibitors of the binding of urokinase to the urokinase receptor. The peptides have the general structural formula (I): X.sup.1 -[X.sup.2 ].sub.n -X.sup.3 -X.sup.4 -K-Y-F-X.sup.5 -X.sup.6 -I-X.sup.7 -W-[X.sup.8 ].sub.m (I) in which X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5, X.sup.6, X.sup.7 and X.sup.8 each denote an aminocarboxylic acid, n and m are each independently 0 or 1, K denotes an aminocarboxylic acid with a lysine side chain, Y denotes an aminocarboxylic acid with a tyrosine side chain, F denotes an aminocarboxylic acid with a phenyl-alanine side chain, I denotes an aminocarboxylic acid with an isoleucine side chain, W denotes an aminocarboxylic acid with a tryptophan side chain, and the monomeric building blocks are linked by --CONR.sup.1 -- or --NR.sup.1 CO-- bonds where R.sup.1 in each case independently denotes hydrogen, methyl or ethyl, and pharmaceutically compatible salts and derivatives thereof.

La actual invención proporciona los peptides como inhibidores del atascamiento del urokinase al receptor del urokinase. Los peptides tienen el fórmula estructural general (i): X.sup.1 -[X.sup.2 ].sub.n - X.sup.3 - X.sup.4 - K-Y-F-X.sup.5 - X.sup.6 - I-X.sup.7 - W-[X.sup.8 ].sub.m (i) en los cuales X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5, X.sup.6, X.sup.7 y X.sup.8 cada uno denotan un ácido aminocarboxylic, n y m son cada uno independientemente 0 o 1, K denota un ácido aminocarboxylic con una cadena lateral del lysine, Y denota un ácido aminocarboxylic con una cadena lateral del tyrosine, F denota un ácido aminocarboxylic con una cadena lateral del phenyl-alanine, I denota un ácido aminocarboxylic con una cadena lateral del isoleucine, W denota un ácido aminocarboxylic con una cadena lateral del tryptophan, y los bloques de edificio monomeric se ligan cerca -- CONR.sup.1 -- o -- NR.sup.1 CO -- enlaces donde R.sup.1 en cada caso denota independientemente el hidrógeno, metilo o el etilo, y farmacéutico sales y derivados compatibles de eso.