title: Purification and characterization of a Ca2+ -dependent prothrombin activator, multactivase, from the venom of Echis multisquamatus.
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.
authors.affiliation: Department of Biochemistry, Meiji College of Pharmacy, Tokyo.
authors.forename: D
authors.initials: D
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Morita
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004789:Enzyme Activation; D008666:Metalloendopeptidases / Q000737:chemistry / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification; D011516:Prothrombin / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014757:Viper Venoms / Q000737:chemistry / Q000201:enzymology* / Q000302:isolation & purification*
chemical_list: D010455:Peptides; D014757:Viper Venoms; D011516:Prothrombin; D008666:Metalloendopeptidases; C098667:carinactivase; C110246:multactivase; D002118:Calcium