tes d Mohammed Sajid3,4

database [9] and some old assumptions about parasite peptidases are revisited and updated. The hand-curated MEROPS database supplies a high quality snapshot of known peptidases and homologs; the populations and relative similarities of parasite peptidases and model pep-tidases can then be viewed using sequence similarity net-works. This representation provides a useful context for ReviewThey are also used to manipulate the host immune system to elude the immune response [3]. Further, parasite pep-tidases are involved in processing secondary protein modi-fications [5,6] and are used as immunodiagnostic markers of infection. Parasite peptidases can also trigger allergies in humans and other hosts [7]. This review focuses on cysteine peptidases from medi-cally important parasitic protozoa and helminths; an over-view of the cysteine peptidase clans that contain parasit