title: Isolation and preliminary characterization of a 48-kilodalton metalloproteinase from the excretory/secretory components of the frontal glands of Porocephalus pentastomids.
abstract: Porocephalid pentastomids possess prominent paired frontal glands which discharge secretion through large ducts onto the cuticle in the region of the cephalothorax. We have purified and partially characterized a 48-kDa protein with proteolytic activity from the major secretory cell type in the glands of Porocephalus crotali, removed from the tissues of rodent intermediate hosts. It comprises 30% of total protein isolated from secretory droplets. Antibody to the enzyme was detectable at 50 days post-infection in sera from infected hosts indicating in vivo release. Biochemical characterization has shown the enzyme is an elastase-like metallo proteinase with an alkaline pH dependency. In addition to the proteinase, 3 or 4 peptides (16-22.0 kDa) were visible in SDS-PAGE gels of gland cell proteins; on boiling, these peptides aggregated to 31 kDa. No antibody response to these peptides could be detected in infected hosts although they can be harvested from culture media following in vitro maintenance of the parasite. Possible immunomodulatory functions of these proteins are discussed. Preliminary data concerning frontal gland proteins of the related species Porocephalus clavatus are included for comparative purposes.
authors.affiliation: Department of Biological Sciences, University of Dundee, Scotland, U.K.
authors.forename: D A
authors.initials: DA
authors.lastname: Jones
authors.forename: J
authors.initials: J
authors.lastname: Riley
authors.forename: N W
authors.initials: NW
authors.lastname: Kerby
authors.forename: D P
authors.initials: DP
authors.lastname: Knox
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002853:Chromatography, Liquid; D003445:Crustacea / Q000201:enzymology* / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D008666:Metalloendopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D010272:Parasitic Diseases / Q000469:parasitology; D051381:Rats; D011919:Rats, Inbred Strains; D012911:Snakes / Q000469:parasitology
chemical_list: D008666:Metalloendopeptidases