background: protozoa related to trypanosome family including leishmania , synthesize enzymes to escape from drug therapy. one of them is ptr1 that its enzymatic activity is similar to dihydrofolate reductase (dhfr). dihydrofolate reductase - thymidylate synthase has a major role in dna synthesis, if it is inhibited, the result would be the death of parasite. since ptr1 activity is similar to dh...