The protein Potato Carboxypeptidase Inhibitor (PCI) has been found to inhibit growth of the parasite Plasmodium falciparumwhich causes malaria. Specifically, the therapeutic target to which said PCI joins in order to inhibit the growth of the parasite is a metallocarboxypeptidase of P. Falciparum known as PfNnal, which converts said metalocarboxypeptidase into a therapeutic target useful for identifying novel compounds in the treatment of malaria.