Bothrops moojeni venom kills Leishmania spp. with hydrogen peroxide generated by its L-amino acid oxidase

Leishmaniasis is an endemic tropical disease in South America, with few the rapeutic approaches. Snake venoms are complex protein mixtures with biologi cal actions that could be used as tools for drug development. Here we show that Bothrops moojeni crude venom presented a killing effect in vitro again st Leishmania spp. promastigotes, but not with amastigotes, as determined b y a viability assay using the mitochondrial oxidative function. Purificatio n of active fractions from crude venom was performed by molecular exclusion and ion exchange chromatography. Anti-Leishmania and L-amino acid oxidase (L-AAO, EC.1.4.3.2.) activities co-eluted in the same fractions. The molecu lar weight of the active enzyme was estimated to be 140 kDa by molecular ex clusion chromatography, and 69 kDa by SDS-PAGE, with a 4.8 isoelectric poin t. Using substrate subtraction and catalase for scavenging, the action of L -AAO was demonstrated to be hydrogen-peroxide-dependent. (C) 2001 Academic Press.