title: Proteinase inhibitory activity released from the horseshoe crab blood cell during exocytosis.
abstract: The blood cell of the horseshoe crab, Limulus, is packed with granules that can be stimulated to release their contents by exocytosis. We have identified a family of proteinase inhibitors in the released materials. Included is a factor similar to the alpha 2-macroglobulin homologue present in the plasma and acid-stable and acid-instable active-site inhibitors. The acid-stable factor is active against both serine (trypsin, chymotrypsin) and metal (thermolysin) proteinases. The trypsin- and chymotrypsin-inhibitory activity has a molecular weight of 6100, as determined by gel-filtration chromatography.
authors.forename: P B
authors.initials: PB
authors.lastname: Armstrong
authors.forename: J P
authors.initials: JP
authors.lastname: Quigley
mesh_terms: D000818:Animals; D001586:Benzoylarginine Nitroanilide / Q000378:metabolism; D002850:Chromatography, Gel; D002918:Chymotrypsin / Q000378:metabolism; D005089:Exocytosis; D006737:Horseshoe Crabs; D008970:Molecular Weight; D011480:Protease Inhibitors / Q000097:blood*; D013820:Thermolysin / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
chemical_list: D011480:Protease Inhibitors; D001586:Benzoylarginine Nitroanilide; D002918:Chymotrypsin; D014357:Trypsin; D013820:Thermolysin