Fig 2.

MBP-PfShelph2 hydrolyzes tyrosine-phosphorylated peptides. (A) Purified WT MBP-PfShelph2 (20 μg/ml) was incubated with the indicated phosphorylated substrates for 2 h at 37°C. After addition of malachite green reagent, the OD₆₂₀ was measured and converted to pmol of phosphate. The data are representative of three independent experiments, each performed in duplicate. The error bars indicate standard deviations. (B) MBP-PfShelph2 activity was measured using the pNPP assay in the presence of sodium orthovanadate at the indicated concentrations. (C) MBP-PfShelph2 activity was measured as for panel B in the presence of S/T phosphatase inhibitors at the indicated concentrations. (D) The S/T phosphatase inhibitors were tested using PP1 (Sigma) as in panel A.