Purification and Characterization of Protein Tyrosine Phosphatase from Trypanosoma Evansi

Novel protein tyrosine phosphatase (PTPase) isolated from Trypanosoma evansi was purified and characterized, revealing the kinetic parameters to aid in the design of trypanocide that target the pathogenic activity of the enzyme in trypanosomiasis. Healthy albino rats of average weight 190g were inoculated intraperitoneally with 0.2ml of Trypanosoma evansi-infected host blood in normal saline. The parasites were harvested, and lysed following three cycles of freezing and thawing. PTPase was assayed with 10 mmol/L para-nitrophenylphosphate at 37 C for 10 minutes. Assay specificity of PTPase was verified by adding sodium orthovanadate. The PTPase was purified following ammonium sulphate precipitation and Gel filtration on Sephadex G75 column, characterized by determining the optimum temperature, temperature stability, optimum pH, pH stability, effects of divalent cations and initial velocity studies. Results revealed 13.23 purification fold and a yield of 41.45 %. The PTPase had a molecular weight of 31.2 kDa, broad temperature and pH range with optima of 70 0C and 5.0 respectively. Initial velocity studies revealed a KM and Vmax of 3.44mM and 0.19mol/min respectively. The PTPase activity was enhanced by Ca2+ and inhibited by Zn2+. These findings, especially the inclusion of Zn2+ could aid in the design of trypanocides for attenuating trypanosome pandemic.