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  • Title: Purification and characterization of a Ca2+ -dependent prothrombin activator, multactivase, from the venom of Echis multisquamatus.
    Author: Yamada D, Morita T.
    Journal: J Biochem; 1997 Nov; 122(5):991-7. PubMed ID: 9443815.
    Abstract:
    We previously found a novel Ca2+-dependent prothrombin activator, designated as carinactivase-1, in Echis carinatus leucogaster venom [D. Yamada, F. Sekiya, and T. Morita (1996) J. Biol. Chem. 271, 5200-5207]. Of the Viperidae snake venoms examined, the Echis multisquamatus venom had the strongest carinactivase-like activity. We isolated and characterized the carinactivase-like prothrombin activator in E. multisquamatus venom. From 50 mg of E. multisquamatus venom, we isolated 2.3 mg of a Ca2+-dependent prothrombin activator designated as multactivase. Unlike other Echis snake venoms, the E. multisquamatus venom contained no ecarin-like Ca2+-independent prothrombin activator. The structure and function of multactivase are similar to those of carinactivase. Multactivase is composed of a catalytic subunit with metalloprotease activity and a regulatory subunit comprising two homologous polypeptides bound by S-S bridge(s), and it activates prothrombin via recognition of the Ca2+-bound conformation of its Gla domain. We developed a chromogenic assay involving multactivase for normal prothrombin activity in plasma from individuals orally administered anticoagulants. The normal prothrombin activity, as a percentage, measured with multactivase was highly correlated with the prothrombin time. Multactivase is useful for the simple quantification of normal prothrombin in plasma from warfarin-treated individuals.
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