20S proteolytic activity during <i>T.cruzi in vitro</i> metacyclogenesis.

Peptidase activities were assayed using 100 µg of proteins of crude extratct from each of the six stages of cell differentiation. Chymotrypsin-like, trypsin-like, and caspase-like activities in presence or absence of MG132, were determined by fluorimetric quantification of the substrates Z-Gly-Gly-Arg-AMC, Suc-Leu-Leu-Val-Tyr-AMC and N-Cbz-Leu-Leu-Glu-β-NA, at 380 nm excitation/440 nm emissions, respectively. The results are presented in Relative Fluorescence Unit (RFU). Values shown are mean ± standard deviation from three independent experiments.