Thiol proteinase expression and pathogenicity of Entamoeba histolytica

J Clin Microbiol. 1989 Dec;27(12):2772-7. doi: 10.1128/JCM.27.12.2772-2777.1989.


Expression of the 56-kilodalton (kDa) neutral thiol proteinase has been shown to correlate with the potential of clinical isolates of Entamoeba histolytica to produce invasive disease. A 56-kDa band was identified by gelatin substrate gel electrophoresis in 10 of 10 isolates from patients with colitis or amebic liver abscesses, but in only 1 of 10 isolates from asymptomatic patients. Pathogenic isolates appear capable of releasing significantly larger quantities of the proteinase, as measured by cleavage of a synthetic peptide substrate, ZRR-AMC (benzyloxy-carbonyl-arginine-arginine-4-amino-7-methylcoumarin). We have also shown that the proteinase is released during the course of clinical invasive amebic disease, as demonstrated by the presence of circulating antibodies detectable by enzyme-linked immunosorbent assay. These studies support the importance of the 56-kDa thiol proteinase in the pathogenesis of invasive amebiasis.

Publication types

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

MeSH terms

  • Amebiasis / parasitology*
  • Animals
  • Cysteine Endopeptidases / analysis
  • Cysteine Endopeptidases / biosynthesis*
  • Dysentery, Amebic / parasitology
  • Electrophoresis, Polyacrylamide Gel
  • Electrophoresis, Starch Gel
  • Entamoeba histolytica / enzymology*
  • Entamoeba histolytica / pathogenicity
  • Entamoebiasis / parasitology*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Liver Abscess, Amebic / parasitology


  • Cysteine Endopeptidases