Thromb Haemost 1990; 64(02): 235-238
DOI: 10.1055/s-0038-1647292
Original Article
Schattauer GmbH Stuttgart

Isolation and Characterization of a Coagulation Factor Xa Inhibitor from Black Fly Salivary Glands

John W Jacobs
*   The Department of Biological Chemistry, University of Arizona, Tucson, AZ, USA
Eddie W Cupp
**   The Department of Entomology, Merck Sharp & Dohme Research Laboratories, West Point, PA, USA
Mohinder Sardana
*   The Department of Biological Chemistry, University of Arizona, Tucson, AZ, USA
Paul A Friedman
***   The Department of Pharmacology, University of Arizona, Tucson, AZ, USA
› Author Affiliations
Further Information

Publication History

Received 20 December 1989

Accepted after revision 20 April 1990

Publication Date:
25 July 2018 (online)


We have discovered and charact enzed a novel coagulation factor Xa inhibitor from the salivary gland of the black fly, Simulium vittatum. Salivary glands were surgically dissected from the flies and a crude salivary gland extract was tested for inhibition of a number of coagulation assays. The gland extract inhibited both thrombin and factor Xa. Tic purify further the factor Xa inhibitor, a factor Xa affinity column was utilized. Final purification of the black fly factor Xa inhibitor was achieved by reverse-phase C8 microbore high pressure liquid chromatography. Inhibition of factor Xa was nearly stoichiometric by the purified inhibitor with no inhibitor of thrombin detected. SDSpolyacrylamide gel electrophoresis indicated the inhibitor had a molecular weight of 18,000 and sequence analysis of the inhibitor revealed a blocked amino terminus. These data indicate that the blood-sucking black fly has evolved a highly potent inhibitor of mammalian coagulation factor Xa to disrupt its host normal hemostatic clotting mechanisms.