title: Developmentally regulated zinc metalloproteinases from third- and fourth-stage larvae of the ovine nematode Haemonchus contortus.
abstract: Parasitic third-stage larvae of the sheep abomasal nematode Haemonchus contortus develop and molt in vitro to the fourth stage (L4) in 48-72 hr, at which time they begin feeding. Coincident with the third molt, larvae begin to secrete significant amounts of protein into culture fluids, including a zinc metalloproteinase. This culture-derived zinc metalloproteinase differs from a previously described metalloproteinase from infective third-stage larvae (L3[2M]), which mediates the ecdysis process. These differences include time of expression, molecular mass, and substrate specificity. The purified proteinase, from cultures of L4, has a molecular weight of approximately 46 kDa, functions as an endopeptidase, and digests several native proteins of host origin including fibrinogen and fibronectin.
authors.affiliation: US Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705, USA.
authors.forename: H R
authors.initials: HR
authors.lastname: Gamble
authors.forename: R H
authors.initials: RH
authors.lastname: Fetterer
authors.forename: L S
authors.initials: LS
authors.lastname: Mansfield
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001391:Azo Compounds / Q000378:metabolism; D002364:Caseins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003094:Collagen / Q000378:metabolism; D004396:Coloring Agents / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005340:Fibrinogen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D006189:Haemonchus / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007328:Insulin / Q000378:metabolism; D007797:Laminin / Q000378:metabolism; D007814:Larva / Q000201:enzymology; D008666:Metalloendopeptidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011480:Protease Inhibitors / Q000494:pharmacology; D012756:Sheep; D013379:Substrate Specificity; D015032:Zinc
chemical_list: D001391:Azo Compounds; D002364:Caseins; D004396:Coloring Agents; D005353:Fibronectins; D007328:Insulin; D007797:Laminin; D011480:Protease Inhibitors; C026018:azocasein; C028470:Azocoll; D005340:Fibrinogen; D003094:Collagen; D008666:Metalloendopeptidases; D015032:Zinc