Fig 2.

EhMSP-1 has protease activity that is inhibited by the Zn²⁺ metalloprotease inhibitor phenanthroline. An anti-EhMSP-1 scFv recombinant monoclonal antibody or control scFv antibody was used for immunoprecipitation from HM-1:IMSS strain E. histolytica lysates. (A) Immunoblot demonstrating specific immunoprecipitation of EhMSP-1. Immunoprecipitated proteins were separated by SDS-PAGE, transferred to a PVDF membrane, and probed with affinity-purified anti-EhMSP-1 rabbit polyclonal IgG. Whole E. histolytica lysates were run in an adjacent lane as a positive control. (B) Detection of metalloprotease activity. Protease activity of immunoprecipitated protein was measured in the presence or absence of 15 mM phenanthroline. Trypsin (66.7 μg/ml) was used as a positive control for the assay and a negative control for phenanthroline inhibition. The graph shows mean optical density (O.D.) at 450 nm and SE measured for three independent immunoprecipitation experiments. *, P = 0.03 in each case.