Four superoxide dismutase (SOD) activities (SOD I, II, III, and IV) have been characterized in the epimastigote
form of
Trypanosoma cruzi
. The total extract was subjected to two successive ammonium sulphate additions between
35 and 85%, and the resulting fraction was purified using two continuous chromatography processes (ion exchange
and filtration). Enzymes were insensitive to cyanide but sensitive to hydrogen peroxide, properties characteristic of
iron-containing SODs. The molecular masses of the different SODs were 20 kDa (SOD I), 60 kDa (SOD II), 50 kDa
(SOD III) and 25 kDa (SOD IV), whereas the isoelectric points were 6.9, 6.8, 5.2 and 3.8, respectively. Subcellular
location and digitonin experiments have shown that these SODs are mainly cytosolic, with small amounts in the low-
mass organelles (SOD II and SOD I) and the mitochondrion (SOD III), where these enzymes play an important role
in minimizing oxidative damage.Financial support: CGL2006-27889-E/BOS, Ministerio de Ciencia y Tecnología