A broad spectrum Kunitz type serine protease inhibitor secreted by the hookworm Ancylostoma ceylanicum

Aaron M. Milstone, Lisa M. Harrison, Richard D. Bungiro, Petr Kuzmič, Michael Cappello

Research output: Contribution to journalArticlepeer-review

Abstract

Although blood-feeding hookworms infect over a billion people worldwide, little is known about the molecular mechanisms through which these parasitic nematodes cause gastrointestinal hemorrhage and iron deficiency anemia. A cDNA corresponding to a secreted Kunitz type serine protease inhibitor has been cloned from adult Ancylostoma ceylanicum hookworm RNA. The translated sequence of the A. ceylanicum Kunitz type inhibitor 1 (AceKI-1) cDNA predicts a 16-amino acid secretory signal sequence, followed by a 68-amino acid mature protein with a molecular mass of 7889 daltons. Recombinant protein (rAceKI-1) was purified from induced lysates of Escherichia coli transformed with the rAceKI-1/pET 28a plasmid, and in vitro studies demonstrate that rAceKI-1 is a tight binding inhibitor of the serine proteases chymotrypsin, pancreatic elastase, neutrophil elastase, and trypsin. AceKI-1 inhibitory activity is present in soluble protein extracts and excretory/secretory products of adult hookworms but not the infective third stage larvae. The native AceKI-1 inhibitor has been purified to homogeneity from soluble extracts of adult A. ceylanicum using size exclusion and reverse-phase high pressure liquid chromatography. As a potent inhibitor of mammalian intestinal proteases, AceKI-1 may play a role in parasite survival and the pathogenesis of hookworm anemia.

Original languageEnglish (US)
Pages (from-to)29391-29399
Number of pages9
JournalJournal of Biological Chemistry
Volume275
Issue number38
DOIs
StatePublished - Sep 22 2000

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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