Schistosome invasion of human skin and degradation of dermal elastin are mediated by a single serine protease

J Biol Chem. 2000 Dec 8;275(49):38667-73. doi: 10.1074/jbc.M006997200.


Aquatic larvae (cercariae) of the trematode parasite Schistosoma mansoni rapidly penetrate human skin by degrading host proteins including elastin. Two serine proteases, one chymotrypsin-like and the second trypsin-like, have been proposed to be involved. To evaluate the relative roles of these two proteases in larval invasion, both were purified, identified by sequence, and then biochemically characterized. The trypsin-like activity was resolved into two distinct serine proteases 76% similar in predicted amino acid sequence. Southern blot analysis, genomic polymerase chain reaction, and immunolocalization demonstrated that the trypsin-like proteases are in fact not from the schistosome, but are released with larvae from the snail host Biomphalaria glabrata. Invasion inhibition assays using selective inhibitors confirmed that the chymotrypsin-like protease is the enzyme involved in skin penetration. Its ability to degrade skin elastin was confirmed, and the three sites of cleavage within elastin help define a new family of elastases.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biomphalaria / enzymology
  • Chromatography, Affinity
  • Chromatography, Gel
  • Chymotrypsin / metabolism
  • Cloning, Molecular
  • Elastin / metabolism*
  • Humans
  • Kinetics
  • Larva
  • Molecular Sequence Data
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Schistosoma mansoni / enzymology*
  • Schistosoma mansoni / genetics
  • Schistosoma mansoni / pathogenicity
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Serine Endopeptidases / chemistry
  • Serine Endopeptidases / genetics*
  • Serine Endopeptidases / metabolism*
  • Skin / metabolism*
  • Skin / parasitology*


  • Recombinant Proteins
  • Elastin
  • Serine Endopeptidases
  • Chymotrypsin

Associated data

  • GENBANK/AF302259
  • GENBANK/AF302260