Summary
The present work reports the discovery and charactenzation of an anticoagulant protein
in the salivary gland of the giant bloodsucking leech, H. ghilianii, which is a specific and potent inhibitor of coagulation factor Xa. The inhibitor,
purified to homogeneity, displayed subnanomolar inhibition of bovine factor Xa and
had a molecular weight of approximately 15,000 as deduced by denaturing SDS-PAGE.
The amino acid sequence of the first 43 residues of the H. ghilianii derived inhibitor displayed a striking homology to antistasin, the recently described
subnanomolar inhibitor of factor Xa isolated from the Mexican leech, H. officinalis. Antisera prepared to antistasin cross-reacted with the H. ghilianii protein in Western Blot analysis. These data indicate that the giant Amazonian leech,
H. ghilianii, and the smaller Mexican leech, H. officinalrs, have similar proteins which disrupt the normal hemostatic clotting mechanisms in
their mammalian host’s blood.
Keywords
Leech - Haementeria - Anticoagulant - Factor Xa - Antistasin
