A DIPEPTIDYLPEPTIDASE SECRETED BY FASCIOLA-HEPATICA

A dipeptidylpeptidase (DPP) was isolated from Fasciola hepatica by gel -filtration and ion-exchange chromatography. The exoproteinase is secr eted by newly excysted juveniles, immature and mature flukes. The live r fluke DPP is a serine proteinase of molecular weight > 200 kDa and d iffers from previously characterized mammalian DPPs in its substrate p reference and susceptibility to inactivation by inhibitors. The parasi te DPP may function in the latter stages of the proteolytic digestion of host macromolecules. In this manner, the enzyme may be important in providing the parasite with dipeptides that could be absorbed through the intestine as nutrient.