“…Studies related to GSS and TS inhibitors, using glutathione analogs, showed that the substitution of the L-Cys in glutathione by hydrophobic amino acids, as L-leu and L-val, result in efficient non-competitive inhibitors of these enzymes. However, overall, these inhibitors did not appear to be efficient against Leishmania sp., probably due to the action of proteases and to the difficulty of the compounds to penetrate through cellular membrane [19,20]. Taking these inhibitors as prototypes, two series of tripeptids were synthesized; in one series, beside the change of aminoacids, benzyl esther radicals were included on C and N terminal groups of the glutamic acid (ASC-I-74A, ASC-I-75A, ASC-I-74B and ASC-I-75B), which increase the lipophilicity of the molecule.…”