ENTRY       EC 3.4.21.60
NAME        Scutelarin
            Taipan activator
CLASS       Hydrolases
            Acting on peptide bonds (peptidases)
            Serine endopeptidases
REACTION    Selective cleavage of Arg+Thr and Arg+Ile in prothrombin to form
            thrombin and two inactive fragments
SUBSTRATE   Prothrombin
            H2O
PRODUCT     Thrombin
EFFECTOR    Phospholipid
            Calcium
COMMENT     From the venom of the Taipan snake (Oxyuranus scutellatus).
            Converts prothrombin to thrombin in the absence of coagulation
            Factor Va, and is potentiated by phospholipid and Ca2+.
            Specificity is similar to that of Factor Xa.  Binds Ca2+ via
            gamma-carboxylglutamic acid residues.  Formerly EC 3.4.99.28.
            Similar enzymes are known from the venom of other Australian
            elapid snakes Pseudonaja textilis textilis, Oxyuranus
            microleidotus and Demansia nuchalis affinis.
DBLINKS     University of Geneva ENZYME DATA BANK: 3.4.21.60
            WIT (What Is There) Metabolic Reconstruction: 3.4.21.60
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