Schistosoma mansoni: Isolation and characterization of Smpi56, a novel serine protease inhibitor

Yoseph Ghendler, Ruth Arnon, Zvi Fishelson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


Tegumental extracts from adult worms of Schistosoma mansoni contain an inhibitory activity to the S. mansoni 28-kDa serine protease and to pancreatic elastase. By using biotinylated elastase and streptavidin-agarose, the postulated protease inhibitor has been isolated from the crude worm extract in a single step. Monospecific rabbit antibodies raised against the protease inhibitor have immunoprecipitated a 56-kDa [35S]Met-labeled serine protease inhibitor which was designated Smpi56 (S. mansoni protease inhibitor, 56 kDa). Smpi56 binds tightly to and inhibits the 28-kDa protease of S. mansoni and pancreatic and neutrophil elastase but not papain, pepsin, thrombin, trypsin, chymotrypsin, proteinase K, urokinase and acetylcholinesterase. The biological function of Smpi56 is still not known, but in view of its elastase inhibitory activity it may be speculated that the parasite is employing Smpi56 to protect itself from activated neutrophils. Smpi56 may also potentially protect the parasite from its endogenous 28-kDa protease.

Original languageEnglish
Article number71013
Pages (from-to)121-131
Number of pages11
JournalExperimental Parasitology
Issue number2
StatePublished - Mar 1994
Externally publishedYes


  • Elastase
  • Neutrophil
  • Schistosoma mansoni
  • Trematode


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