Brugia pahangi: identification and characterization of an aminopeptidase associated with larval molting

The third-stage larvae (L3) of the filarid parasite Brugia pahangi were surveyed for protease activity beginning with release from the mosquito vector through molting to the fourth-stage larvae (L4). A metalloaminopeptidase with a substrate preference for phenylalanine was released during the molting process. A screen of aminopeptidase inhibitors identified H-boroPhenylalanine-(pinacol) as highly effective, with a Ki of 1.3 x 10(-11) M. This peptidase inhibitor also arrested molting of L3 larvae in vitro at a concentration of 100 microM.