Tartrate-resistant phosphatase type 5 in Trypanosoma cruzi is important for resistance to oxidative stress promoted by hydrogen peroxide.

Trypanosoma cruzi (the causative agent of Chagas disease) presents a complex life cycle that involves adaptations in vertebrate and invertebrate hosts. As a protozoan parasite of hematophagous insects and mammalian hosts, T. cruzi is exposed to reactive oxygen species (ROS). To investigate the functionality of T. cruzi tartrate-resistant acid phosphatase type 5 (TcACP5), we cloned, superexpressed and purified the enzyme. Purified TcACP5 exhibited a Vmax and apparent Km for pNPP hydrolysis of 7.7 ± 0.2 nmol pNP × μg-1 × h-1 and 169.3 ± 22.6 μM, respectively. The pH dependence was characterized by sharp maximal activity at pH 5.0, and inhibition assays demonstrated its sensitivity to acid phosphatase inhibitors. Similar activities were obtained with saturating concentrations of P-Ser and P-Thr as substrates. The enzyme metabolizes hydrogen peroxide (H2O2) in vitro, and parasites superexpressing this enzyme were more resistant to oxidative stress promoted by H2O2. Taken together, these results suggest that TcACP5 plays a central role in phosphoryl transfer and redox reactions.