The cytotoxicity of MnPs/Asc incancer cells is largely attributedto the production and accumulation of H2O2 viaMnP-catalyzed autoxidation of Asc; in these studies, the MnP/Asc effectis suppressed or decreased by treatment with catalase.,, To investigate whether a similarmechanism occurs in leishmaniasis after MnP ethyl/Asc treatment, catalase,an enzyme that efficiently converts H2O2 intowater and oxygen, was added to the parasite cultures. The gene discussed is CAT; the disease is leishmaniasis.