Hementerin

Hementerin is a protease, i.e., it carries out an enzymatic cleaving of a plasma protein involved in rapid blood coagulation called fibrinogen. The absence of a significant amount of plasma fibrinogen retards coagulation, thus it is a naturally occurring anticoagulant. Hementerin breaks the alpha (FGA), gamma (FGG) and beta (FGB) chains, by degrading cross-linked fibrin. It has no degrading action on amide, plasminogen and casein. In addition, hementerin inhibits platelet aggregation induced by collagen via the activation of a nitridergic pathway. Inhibition is probably achieved by enhanced nitric oxide synthase activity. Calcium is a cofactor (ligand) in this activity. The fibrinolytic activity is inhibited by EDTA, a metal chelator agent, which removes zinc from the molecule.^{[citation needed]}

Hementerin is an 80 kDa protein. A fragment of 30 aminoacids of its N-terminal sequence is known: XTLSEPEPTC SIEYFRYQAI EDCEYSISVK.

• Hementerin. UNIPROT. Last modified March 21, 2012. Version 4.
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• Rosenfeld, G.; Hampe, O.G.; Kelen, E.M.A. (1959). "Coagulant and fibrinolytic activity of animal venoms; determination of coagulant and fibrinolytic index of different species". Memórias do Instituto Butantan. 29: 143–163. PMID 13743435.