Ancylostoma factor Xa inhibitor: partial purification and its identification as a major hookworm-derived anticoagulant in vitro.

Soluble protein extracts from adult Ancylostoma hookworms were found to contain an anticoagulant activity that markedly prolonged both the prothrombin time (PT) and partial thromboplastin time (PTT). By chromogenic peptide substrate and clotting time assays, the anticoagulant activity was attributed to a specific inhibitor of clotting factor Xa. The hookworm anticoagulant was partially purified by ion-exchange column chromatography. Those column fractions containing anti-Xa activity by chromogenic assay also prolonged the PT and PTT as well as the factor X (Stypven) clotting time. These data suggest that this potent factor Xa inhibitor is a major anticoagulant from the adult Ancylostoma hookworm.