Figure 2

The catalytic subdomain IIa is sufficient to have enzymatic activity of Pf -calpain. A) Purified recombinant Pf cal-IIa (rPf cal-IIa) and endogenous Pf-calpain were confirmed by Western blot analysis using anti-Pf CapnA antibody (α-Cal) and anti-poly-His Tag antibody (α-His). M, size marker; lane 1, un-induced E. coli cell lysate; lane 2, purified rPf cal-IIa; Pf, protein extracts of P. falciparum. B) Effect of pH on the activity of rPf cal-IIa was assessed by fluorogenic substrate assay. The activity of rPf cal-IIa and the effects of protease inhibitors were analysed by C) gelatin zymography and D) the fluorogenic substrate assay. C) The proteolytic activity is shown in clear zone on SDS gels. D) Data are presented as mean ± S.D. Statistical analysis was performed using the student’s t-test. **p < 0.01.