Identification and characterization of an asparaginyl endopeptidase from Angiostrongylus cantonensis

Parasitol Res. 2014 Jun;113(6):2143-52. doi: 10.1007/s00436-014-3866-0. Epub 2014 Apr 3.


Asparaginyl endopeptidase, also known as legumain, is a family of cysteine proteases in many organisms. In this study, an asparaginyl endopeptidase (Ac-AEP) was identified from the cDNA library of Angiostrongylus cantonensis. The full-length of Ac-AEP was determined to be 1,472 bp with an open reading frame of 1,341 bp encoding a putative protein with 446 amino acids. This putative protein was determined to have 37-65% identity in the amino acid sequences of the asparaginyl endopeptidases of other parasitic helminths. By real-time quantitative PCR analysis, Ac-AEP was revealed to be more abundantly expressed in the female adult worms than in other development stages. A recombinant asparaginyl endopeptidase (rAc-AEP) was then produced by a Pichia pastoris expression system. Posttranslational modification was shown to occur via N-linked glycosylation in this recombinant enzyme. The proteolytic activity of rAc-AEP was inhibited by iodoacetamide but not affected by E64, pepatain A, AEBSF, and EDTA. Moreover, the purified rAc-AEP was recognized by IgG in serum samples from BALB/c or ICR mice with A. cantonensis infection and patients with eosinophilic meningitis. These findings indicate that the rAc-AEP may have the potential for detecting A. cantonensis infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Angiostrongylus cantonensis / enzymology*
  • Angiostrongylus cantonensis / genetics
  • Animals
  • Antibodies, Helminth
  • Antibody Specificity
  • Base Composition
  • Cloning, Molecular
  • Cysteine Endopeptidases / chemistry
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / metabolism*
  • Female
  • Gene Expression Regulation, Enzymologic
  • Gene Library
  • Humans
  • Immunoglobulin G / blood
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred ICR
  • Molecular Sequence Data
  • Pichia / genetics
  • Pichia / metabolism
  • Strongylida Infections


  • Antibodies, Helminth
  • Immunoglobulin G
  • Cysteine Endopeptidases
  • asparaginylendopeptidase