Abstract
Trypanosoma cruzi epimastigote lysates presented proteolytic activity both at pH 7.0 and at pH 3.0. A proteinase was isolated from these lysates. The isolated proteinase, which is probably an SH-dependent enzyme, was able to hydrolyze hemoglobin at pH 3.0 and both casein and hemoglobin at pH 7.0, but was unable to hydrolyze the esterase synthetic substrate tested. A single enzyme of molecular weight 60,000 could be detected in purified preparations. Antibodies induced by the purified proteinase, shown to be specific for proteinase molecules by line immunoelectrophoresis experiments, reacted with epimastigota of the Y strain and with trypomastigota and amastigota of five different strains tested. Electron microscopy observations of peroxidase labeled preparations indicated that the proteinase could be found at the surface of different forms of the parasite.