Parasite Prolyl Oligopeptidases and the Challenge of Designing Che- motherapeuticals for Chagas Disease, Leishmaniasis and African Try-

leishmaniasis and human African trypanosomiasis, respectively. It is estimated that over 10 million people worldwide suf-fer from these neglected diseases, posing enormous social and economic problems in endemic areas. There are no vac-cines to prevent these infections and chemotherapies are not adequate. This picture indicates that new chemotherapeutic agents must be developed to treat these illnesses. For this purpose, understanding the biology of the pathogenic trypano-somatid-host cell interface is fundamental for molecular and functional characterization of virulence factors that may be used as targets for the development of inhibitors to be used for effective chemotherapy. In this context, it is well known that proteases have crucial functions for both metabolism and infectivity of pathogens and are thus potential drug targets. In this regard, prolyl oligopeptidase and oligopeptidase B, both members of the S9 serine protease family, have been shown to play important roles in the interactions of pathogenic protozoa with their mammalian hosts and may thus be con-sidered targets for drug design. This review aims to discuss structural and functional properties of these intriguing en-zymes and their potential as targets for the development of drugs against Chagas disease, leishmaniasis and African try-panosomiasis