Thromb Haemost 1984; 52(02): 117-120
DOI: 10.1055/s-0038-1661152
Original Article
Schattauer GmbH Stuttgart

Role of Endogenous Proteinase Inhibitors in the Regulation of the Blood Clotting System of the Horseshoe Crab, Limulus Polyphemus

Authors

  • Peter B Armstrong

    1   The Marine Biological Laboratory, Woods Hole, MA, U.S.A.
    2   The Department of Zoology, University of California, Davis, CA, U.S.A.
  • Jack Levin

    1   The Marine Biological Laboratory, Woods Hole, MA, U.S.A.
    3   The Departments of Laboratory Medicine and Medicine, University of California School of Medicine, San Francisco, CA, U.S.A.
  • James P Quigley

    1   The Marine Biological Laboratory, Woods Hole, MA, U.S.A.
    4   The Department of Microbiology and Immunology, Downstate Medical Center, State University of New York, Brooklyn, NY, U.S.A.
Further Information

Publication History

Received 14 February 1984

Accepted 14 June 1984

Publication Date:
19 July 2018 (online)

Summary

Blood clotting in Limulus is dependent on the activity of a proteinase which converts the zymogen, coagulogen, into a form that undergoes polymerization to form the clot. The abilities of a series of recently discovered endogenous proteinase inhibitors to inhibit this enzyme and thereby serve as potential regulators of its activity were explored. The blood plasma of Limulus contains a single inhibitor that is functionally and structurally homologous to vertebrate α2 macroglobulin. During exocytosis, the blood cells (amebocytes) release a series of inhibitors, including small quantities of the α2 macroglobulin homologue; a low molecular weight, acid-and heat-stable inhibitor; and an acid-labile activity. Of the three inhibitory activities, only the cell-released, acidlabile inhibitor is capable of inhibiting the clotting enzyme.