Characterization of a leucine aminopeptidase from Toxoplasma gondii

The M17 family leucine aminopeptidase (LAP) hydrolyzes amino acids from the N-terminus of peptides. Many LAPs from parasitic protozoa, including Plasmodium, Trypanosoma, and Leishmania, have been intensely investigated because of their crucial roles in parasite biology. In this study, the functional recombinant Toxoplasma gondii LAP (rTgLAP) was expressed in Escherichia coli, and its enzymatic activity against synthetic substrates for aminopeptidase, as well as cellular localization, was determined. The activity was strongly dependent on metal divalent cations, and was inhibited by bestatin, which is an inhibitor for metalloprotease. Our results indicated that TgLAP is a functional aminopeptidase in the cytoplasm of T. gondii.