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Limulus Clotting Enzyme
Limulus clotting enzyme (, ''clotting enzyme'') is an enzyme. This enzyme catalyses the following chemical reaction : Selective cleavage of -Arg18- and -Arg47- bonds in coagulogen to form coagulin and fragments This enzyme is present in the hemocyte granules of horseshoe crabs Limulus and Tachypleus. In the immunity-related clotting pathways of these organisms, it is the final enzyme responsible for the activation of coagulin Coagulin is a gel-forming protein of hemolymph that hinders the spread of invaders by immobilising them. It is produced in the coagulogen form before being cleaved into the active form. In human medicine, coagulation of coagulin is the basis of de .... References External links * {{Portal bar, Biology, border=no EC 3.4.21 ... [...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 substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), 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, 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 Ribozyme, catalytic RNA molecules, called ribozymes. Enzymes' Chemical specificity, specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coagulogen
Coagulin is a gel-forming protein of hemolymph that hinders the spread of invaders by immobilising them. It is produced in the coagulogen form before being cleaved into the active form. In human medicine, coagulation of coagulin is the basis of detection of bacterial endotoxin in the LAL test for parenteral medications. The protein contains a single 175-residue polypeptide chain that is cleaved after Arg-18 and Arg-46 by a Limulus clotting enzyme contained in the hemocyte and activated by a bacterial endotoxin (lipopolysaccharide). Cleavage releases two chains of coagulin, A and B, linked by two disulfide bonds, together with the peptide C. Gel formation results from interlinking of coagulin molecules. The full-length structure of a coagulogen is known (); it shares the same cystine-knot cytokine superfamily (fold) as neurotrophins, with several cystines conserved. The A-B fold wraps around the helical peptide C, forming a compact structure. In crustaceans, hemolymph coagulation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemocyte
A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). Together, these three kinds of blood cells add up to a total 45% of the blood tissue by volume, with the remaining 55% of the volume composed of plasma, the liquid component of blood. Red blood cells Red blood cells or ''erythrocytes'', primarily carry oxygen and collect carbon dioxide through the use of hemoglobin. Hemoglobin is an iron-containing protein that gives red blood cells their color and facilitates transportation of oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs to be exhaled. Red blood cells are the most abundant cell in the blood, accounting for about 40-45% of its volume. Red blood cells are circular, biconcave, disk-shaped and deformable to allow them to squee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseshoe Crab
Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are Chelicerata, chelicerates, most closely related to arachnids, such as spiders and scorpions. Horseshoe crabs live primarily in and around shallow coastal waters on soft, sandy or muddy bottoms. They are generally found in the intertidal zone at spring tide, spring high tides. They are eaten in some parts of Asia, and used as fishing bait, in fertilizer and in science (especially Limulus amebocyte lysate, ''Limulus'' amebocyte lysate). In recent years, population declines have occurred as a consequence of coastal habitat destruction and overharvesting. Tetrodotoxin may be present in one horseshoe crab species, ''Carcinoscorpius rotundicauda''. Fossil records for horseshoe crabs extend back as far as 480 million years ago, with extant forms being living fossils. A 2019 molecular anal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limulus
''Limulus'' is a genus of horseshoe crab, with one extant species, the Atlantic horseshoe crab (''Limulus polyphemus''). One fossil species is currently assigned to the genus though several other species have been named, which have since been assigned to other genera. Currently valid species include: *'' Limulus polyphemus'' (Linnaeus, 1758) *'' Limulus coffini''† Reeside & Harris, 1952- Pierre Shale, United States, Late Cretaceous (Maastrichtian) Doubtful species include:Dunlop, J. A., Penney, D. & Jekel, D. 2013. A summary list of fossil spiders and their relatives. In Platnick, N. I. (ed.) ''The world spider catalog, version 14.0'' American Museum of Natural History, online at http://research.amnh.org/entomology/spiders/catalog/index.html * '' Limulus nathorsti''† Jackson, 1906- Jurassic, Sweden Tentative species: *''" Limulus" decheni''† Zinken, 1862- Paleogene, Germany (considered by some intermediate between ''Limulus'' and ''Tachypleus ''Tachypleus'' is a genu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachypleus
''Tachypleus'' is a genus of south, southeast and east Asian horseshoe crabs in the family Limulidae. Species There are two extant (living) species: * '' Tachypleus gigas'' (Müller, 1785) * '' Tachypleus tridentatus'' ( Leach, 1819) And two extinct species only known from fossil. * '' Tachypleus decheni'' (Zincken, 1862) Upper Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ... Domsen Sands, Germany * '' Tachypleus syriacus'' (Woodward, 1879) Upper Cretaceous ( Cenomanian) Haqel and Hjoula Konservat-Lagerstatten, Lebanon References External links * Xiphosura Extant Cenomanian first appearances Chelicerate genera Taxonomy articles created by Polbot {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
