Snake venoms are a rich source of proteins that act on a variety of physiological systems in mammals. Frequently, hemostatic and nervous systems are targeted by snake venom components, also in the case of the nose-horned viper (Vipera a. ammodytes - Vaa) venom. This venom causes severe clotting disorders and hemorrhage in human. In an attempt to discover innovative procedures and drugs to treat or diagnose hemostatic disorders in man, the venom has been analysed systematically for its haemostatically-active components. In a proteomic approach, proteins that affect integrity of blood vessels, activate or inhibit distinct steps in platelet aggregation and blood coagulation process have been detected and characterized. In our survey we separated the venom in 208 discrete fractions and, using mass spectrometry and bioinformatics, demonstrated that they contain proteins belonging to 13 different families. Among these we identified haemorrhagic proteases, as well as inhibitors of platelet aggregation and agglutination, acting on different platelet receptors and/or their ligands. We identified also components that affect blood coagulation, either activating different steps of this process or inhibiting it. Several more abundant haemostatically-active proteins have already been thoroughly described on the molecular level. To comprehensively characterize also those only scarcely present in the venom we constructed Vaa venom gland cDNA library, from which we have been isolating specific nucleotide sequences, cloning them and preparing recombinant venom proteins for further studies.
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COBISS.SI-ID: 27093031The aim of this work is to prepare a recombinant form of a fibrinolytic metalloproteinase ammodytase, from V. a. ammodytes venom that has a potential to be used as a lead compound in therapy of thromboembolic disorders in men. Recombinant form of the whole enzyme as well as its individual domains will be used in further biochemical and preclinical studies. Further, the work also aims in systematic, proteomic and pharmacological, analysis of the other hemmostatically active components of V. a. ammodytes venom in order to discover components with potential to become new drug candidates to be used for regulation of hemostasis and/or diagnosis of hemostatic disturbances in men.
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In higher molecular mass fractions of the nosehorned viper venom, after gel filtration, we have determined several haemostatically active components. We have isolated enzymatic components (metalloproteinases, serine proteinases and phospholipases A2) and nonenzymatic components (disintegrins and C-type lectinlike proteins). Metalloproteinases and serine proteinases are mostly fibrinogenolytic. We have found a factor X activating serine proteinase and an anticoagulant serine proteinase. We have also identified C-type lectin-like proteins and disintegrins, which have inhibited platelet aggregation. From high molecular mass fraction after gel filtration of the nosehorned viper venom, we have isolated nonhemorrhagic metalloproteinase VaF2 in homogeneous form with αfibrinogenolytic activity.
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COBISS.SI-ID: 36689157