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Venombin A
Venombin A (, ''alpha-fibrinogenase'', ''habutobin'', ''zinc metalloproteinase Cbfib1.1'', ''zinc metalloproteinase Cbfib1.2'', ''zinc metalloproteinase Cbfib2'', ''ancrod'') is an enzyme. This enzyme catalyses the following chemical reaction : Selective cleavage of Arg- bond in fibrinogen, to form fibrin, and release fibrinopeptide A. The specificity of further degradation of fibrinogen varies with species origin of the enzyme This enzyme is a thrombin-like enzyme from venoms of snakes of the viper/rattlesnake group. Examples include ancrod and batroxobin, two serine proteases from snakes that have been used in medical preparations. Applications Venombin A enzymes are the sole representatives of the defibrinogenating agent class of drugs, which by its protease action removes fibrinogen from the circulation. They are thought to act as an antithrombotic by depletion of fibrinogen. They are different from thrombin in that they only cleave fibrinogen alpha chain (those do cleave b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancrod
Ancrod (current brand name: Viprinex) is a defibrinogenating agent derived from the venom of the Malayan pit viper. Defibrinogenating blood produces an anticoagulant effect. Ancrod is not approved or marketed in any country. It is a thrombin-like serine protease. Medical use As of 2017 ancrod was not marketed for any medical use. Pregnancy Category X : Ancrod was not found to be teratogenic in animal studies, but some fetal deaths occurred as a result of placental hemorrhages in animals given high doses; therefore, it should not be used during pregnancy as the defibrinogenation mechanism of ancrod might be expected to interfere with the normal implantation of the fertilized egg. Contraindications and precautions * Known bleeding disorders of any origin or any unexplained excessive bleedings in the past. * Platelet counts of less than 100,000 (even if asymptomatic), exemption : HIT (Heparin- induced thrombocytopenia). * Planned surgery or short before delivery. * Active ulcera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Batroxobin
Batroxobin, also known as reptilase, is a snake venom enzyme with Venombin A activity produced by ''Bothrops atrox'' and ''Bothrops moojeni'', venomous species of pit viper found east of the Andes in South America. It is a hemotoxin which acts as a serine protease similarly to thrombin, and has been the subject of many medical studies as a replacement of thrombin. Different enzymes, isolated from different species of ''Bothrops'', have been called batroxobin, but unless stated otherwise, this article covers the batroxobin produced by ''B. moojeni'', as this is the most studied variety. History Bothrops atrox was described by Carl Linnaeus as early as 1758, but batroxobin, the active compound in its venom, was first described only in 1954 by H. Bruck and G. Salem. In the years following, this first description of batroxobin was shown to have several uses in surgery. Because of the increasing interest in the properties of batroxobin, several studies on its hemostatic effect and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antithrombotic Enzymes
An antithrombotic agent is a drug that reduces the formation of blood clots (thrombi).http://cancerweb.ncl.ac.uk/cgi-bin/omd?antithrombotic Antithrombotics can be used therapeutically for prevention (primary prevention, secondary prevention) or treatment of a dangerous blood clot (acute thrombus). In the U.S., the American College of Chest Physicians publishes clinical guidelines for clinicians for the use of these drugs to treat and prevent a variety of diseases. Processes Different antithrombotics affect different blood clotting processes: * Antiplatelet drugs limit the migration or aggregation of platelets. * Anticoagulants limit the ability of the blood to clot. * Thrombolytic drugs act to dissolve clots after they have formed. See also * Direct Xa inhibitor * Warfarin Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemostatic
An antihemorrhagic (antihæmorrhagic) agent is a substance that promotes hemostasis (stops bleeding). It may also be known as a hemostatic (also spelled haemostatic) agent. Antihemorrhagic agents used in medicine have various mechanisms of action: * Systemic drugs work by inhibiting fibrinolysis or promoting coagulation. * Locally acting hemostatic agents work by causing vasoconstriction or promoting platelet aggregation. Medical uses Hemostatic agents are used during surgical procedures to achieve hemostasis and are categorized as hemostats, sealants and adhesives. They vary based on their mechanism of action, composition, ease of application, adherence to tissue, immunogenicity and cost. These agents permit rapid hemostasis, better visualization of the surgical area, shorter operative times, decreased requirement for transfusions, decreased wound healing time and overall improvement in patient recovery time. Types Systemic There are several classes of antihemorrhagic drug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischaemic Stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly. Signs and symptoms of a stroke may include an inability to move or feel on one side of the body, problems understanding or speaking, dizziness, or loss of vision to one side. Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than one or two hours, the stroke is a transient ischemic attack (TIA), also called a mini-stroke. A hemorrhagic stroke may also be associated with a severe headache. The symptoms of a stroke can be permanent. Long-term complications may include pneumonia and loss of bladder control. The main risk factor for stroke is high blood pressure. Other risk factors include high blood cholesterol, tobacco smoking, obesity, diabetes mellitus, a previous TIA, end-sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmin
Plasmin is an important enzyme () present in blood that degrades many blood plasma proteins, including fibrin clots. The degradation of fibrin is termed fibrinolysis. In humans, the plasmin protein (in the zymogen form of plasminogen) is encoded by the ''PLG'' gene. Function Plasmin is a serine protease that acts to dissolve fibrin blood clots. Apart from fibrinolysis, plasmin proteolyses proteins in various other systems: It activates collagenases, some mediators of the complement system, and weakens the wall of the Graafian follicle, leading to ovulation. Plasmin is also integrally involved in inflammation. It cleaves fibrin, fibronectin, thrombospondin, laminin, and von Willebrand factor. Plasmin, like trypsin, belongs to the family of serine proteases. Plasmin is released as a zymogen called plasminogen (PLG) from the liver into the systemic circulation. Two major glycoforms of plasminogen are present in humans - type I plasminogen contains two glycosylation moieties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venombin AB
Venombin AB (, ''gabonase'', ''okinaxobin II'', ''Bitis gabonica venom serine proteinase'', ''afaâ'', ''cytin'') is an enzyme. This enzyme catalyses the following chemical reaction : Selective cleavage at Arg- bonds in fibrinogen to form fibrin and release fibrinopeptides A and B This enzyme is isolated from the venom of the Gaboon viper ''Bitis gabonica The Gaboon viper (''Bitis gabonica''), also called the Gaboon adder, is a viper species found in the rainforests and savannas of sub-Saharan Africa.McDiarmid RW, Campbell JA, Touré T. 1999. ''Snake Species of the World: A Taxonomic and Geograp ...''. References External links * {{Portal bar, Biology, border=no EC 3.4.21 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibrinogen Alpha Chain
Fibrinogen alpha chain is a protein that in humans is encoded by the ''FGA'' gene. Function The protein encoded by this gene is the alpha component of fibrinogen, a blood-borne glycoprotein composed of three pairs of nonidentical polypeptide chains. Following vascular injury, fibrinogen is cleaved by thrombin to form fibrin, which is the most abundant component of blood clots. In addition, various cleavage products of fibrinogen and fibrin regulate cell adhesion and spreading, display vasoconstrictor and chemotactic activities, and are mitogens for several cell types. Mutations in this gene lead to several disorders, including dysfibrinogenemia, hypofibrinogenemia, afibrinogenemia, and renal amyloidosis. Alternative splicing results in two isoforms that vary in the carboxy-terminus. Interactions Fibrinogen alpha chain has been shown to interact with tissue plasminogen activator. See also *Fibrinogen gamma chain Fibrinogen gamma chain, also known as fibrinogen gamma gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antithrombotic
An antithrombotic agent is a drug that reduces the formation of blood clots (thrombi).http://cancerweb.ncl.ac.uk/cgi-bin/omd?antithrombotic Antithrombotics can be used therapeutically for prevention (primary prevention, secondary prevention) or treatment of a dangerous blood clot (acute thrombus). In the U.S., the American College of Chest Physicians publishes clinical guidelines for clinicians for the use of these drugs to treat and prevent a variety of diseases. Processes Different antithrombotics affect different blood clotting processes: * Antiplatelet drugs limit the migration or aggregation of platelets. * Anticoagulants limit the ability of the blood to clot. * Thrombolytic drugs act to dissolve clots after they have formed. See also * Direct Xa inhibitor * Warfarin Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serine Protease
Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like. Classification The MEROPS protease classification system counts 16 superfamilies (as of 2013) each containing many families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. The majority belong to the S1 family of the PA clan (superfamily) of proteases. For superfamilies, P: superfamily, containing a mixture of nucleophile class families, S: purely serine proteases. superfamily. Within each superfamily, families are designated by their catalytic nucleophile, (S: serine proteases). Substrate specificity Serine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rattlesnake
Rattlesnakes are venomous snakes that form the genera ''Crotalus'' and ''Sistrurus'' of the subfamily Crotalinae (the pit vipers). All rattlesnakes are vipers. Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents. Rattlesnakes receive their name from the rattle located at the end of their tails, which makes a loud rattling noise when vibrated that deters predators or serves as a warning to passers-by. Rattlesnakes are the leading contributor to snakebite injuries in North America, but rarely bite unless provoked or threatened; if treated promptly, the bites are seldom fatal. The 36 known species of rattlesnakes have between 65 and 70 subspecies, all native to the Americas, ranging from British Columbia through Ontario in southern Canada, to central Argentina. The largest rattlesnake, the eastern diamondback, can measure up to in length. Rattlesnakes are preyed upon by hawks, weasels, king snakes, and a variety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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