Proteolytic enzymes of Pomphorhynchus laevis and in three other acanthocephalan species.

Cystacanths and adults of the acanthocephalan Pomphorhynchus laevis were found to release proteolytic enzymes during in vitro culture. Culture media in which cystacanths had been kept contained a trypsinlike collagenolytic proteinase exhibiting a molecular mass of 29 kDa on gelatin substrate gel electrophoresis and a pH optimum at pH 9.0. Samples of adults possessed a trypsinlike collagenolytic proteinase with a molecular mass of 26 kDa and showed a pH optimum at 9.0. Leucine aminopeptidase activity was also present in culture media of adults. An apparent molecular mass of 92 kDa and a pH optimum at pH 8.5 were determined for this proteolytic enzyme. It was concluded that the trypsinlike proteinases of both stages were necessary for the complete and quick perforation of the fishes' intestinal wall, whereas the leucine aminopeptidase seemed to have a nutritional function in the terminal stages of protein hydrolysis at the surface of the worm's body wall. Cystacanths of 3 other species of fish-parasitizing Acanthocephala (Acanthocephalus anguillae, Acanthocephalus lucii, Paratenuisentis ambiguus) did not show any histolytic activity.