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Linamarase
Linamarase, or beta-D-glucosidase (), is an enzyme found in many plants including cassava and the butter bean. In cassava it is found in the cell walls. When the plant is chewed or ground, it exposes the enzyme to compounds like linamarin and lotaustralin which release cyanide compounds that can be lethal to the eater. In humans, chronic toxicity is more likely than death. This action of the enzyme is used by many cultures to process cassava into an edible substance. The enzyme converts the cyanide containing compounds into acetone cyanohydrin Acetone cyanohydrin (ACH) is an organic compound used in the production of methyl methacrylate, the monomer of the transparent plastic polymethyl methacrylate (PMMA), also known as acrylic. It liberates hydrogen cyanide easily, so it is used as a s ..., which spontaneously decomposes to hydrogen cyanide (HCN). The HCN then either dissolves readily in water or is released into the air. Not all cyanide can be removed during processing. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassava
''Manihot esculenta'', common name, commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated as an annual agriculture, crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates. Though it is often called ''yuca'' in parts of Spanish America and in the United States, it is not related to yucca, a shrub in the family Asparagaceae. Cassava is predominantly consumed in boiled form, but substantial quantities are used to extract cassava starch, called tapioca, which is used for food, animal feed, and industrial purposes. The Brazilian farinha, and the related ''garri'' of West Africa, is an edible coarse flour obtained by grating cassava roots, pressing moisture off the obtained grated pulp, and finally drying it (and roasting both in the case of farinha and garri). Cassav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linamarin
Linamarin is a cyanogenic glucoside found in the leaves and roots of plants such as cassava, lima beans, and flax. It is a glucoside of acetone cyanohydrin. Upon exposure to enzymes and gut flora in the human intestine, linamarin and its methylated relative lotaustralin can decompose to the toxic chemical hydrogen cyanide; hence food uses of plants that contain significant quantities of linamarin require extensive preparation and detoxification. Ingested and absorbed linamarin is rapidly excreted in the urine and the glucoside itself does not appear to be acutely toxic. Consumption of cassava products with low levels of linamarin is widespread in the low-land tropics. Ingestion of food prepared from insufficiently processed cassava roots with high linamarin levels has been associated with dietary toxicity, particularly with the upper motor neuron disease known as konzo to the African populations in which it was first described by Trolli and later through the research network initiate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lotaustralin
Lotaustralin is a cyanogenic glucoside found in small amounts in Fabaceae austral trefoil (''Lotus australis''), cassava (''Manihot esculenta''), lima bean (''Phaseolus lunatus''), roseroot (''Rhodiola rosea'') and white clover (''Trifolium repens''), among other plants. Lotaustralin is the glucoside of methyl ethyl ketone cyanohydrin and is structurally related to linamarin, the acetone cyanohydrin glucoside also found in these plants. Both lotaustralin and linamarin may be hydrolyzed by the enzyme linamarase to form glucose and a precursor to the toxic compound hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an .... References {{Glycosides Cyanogenic glycosides Glucosides Plant toxins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetone Cyanohydrin
Acetone cyanohydrin (ACH) is an organic compound used in the production of methyl methacrylate, the monomer of the transparent plastic polymethyl methacrylate (PMMA), also known as acrylic. It liberates hydrogen cyanide easily, so it is used as a source of such. For this reason, this cyanohydrin is also highly toxic. Preparation In the laboratory, this compound may be prepared by treating sodium cyanide with acetone, followed by acidification: : Considering the high toxicity of acetone cyanohydrin, a lab scale production has been developed using a microreactor-scale flow chemistry to avoid needing to manufacture and store large quantities of the reagent. Alternatively, a simplified procedure involves the action of sodium or potassium cyanide on the sodium bisulfite adduct of acetone prepared ''in situ''. This gives a less pure product, one that is nonetheless suitable for most syntheses. Reactions Acetone cyanohydrin is an intermediate en route to methyl methacrylate. Treat ... [...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] |
Phaseolus Lunatus
A lima bean (''Phaseolus lunatus''), also commonly known as the butter bean, sieva bean, double bean, Madagascar bean, or wax bean is a legume grown for its edible seeds or beans. Origin and uses ''Phaseolus lunatus'' is found in Meso- and South America. Two gene pools of cultivated lima beans point to independent domestication events. The Mesoamerican lima bean is distributed in neotropical lowlands, while the other is found in the western Andes. They were discovered in Peru and may have been the first plant that was brought up under civilization by the native farmers. The Andes domestication took place around 2000 BC and produced a large-seeded variety (lima type), while the second, taking place in Mesoamerica around 800 AD, produced a small-seeded variety (Sieva type). By around 1300, cultivation had spread north of the Rio Grande, and, in the 1500s, the plant began to be cultivated in the Old World. The small-seeded (Sieva) type is found distributed from Mexico to Argent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Wall
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism. Cell walls are absent in many eukaryotes, including animals, but are present in some other ones like fungi, algae and plants, and in most prokaryotes (except mollicute bacteria). A major function is to act as pressure vessels, preventing over-expansion of the cell when water enters. The composition of cell walls varies between taxonomic group and species and may depend on cell type and developmental stage. The primary cell wall of land plants is composed of the polysaccharides cellulose, hemicelluloses and pectin. Often, other polymers such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae possess cell walls made of glycoproteins and polysaccharides such as carrageenan and agar that are absent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanide
Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. In inorganic cyanides, the cyanide group is present as the anion . Soluble salts such as sodium cyanide (NaCN) and potassium cyanide (KCN) are highly toxic. Hydrocyanic acid, also known as hydrogen cyanide, or HCN, is a highly volatile liquid that is produced on a large scale industrially. It is obtained by acidification of cyanide salts. Organic cyanides are usually called nitriles. In nitriles, the group is linked by a covalent bond to carbon. For example, in acetonitrile (), the cyanide group is bonded to methyl (). Although nitriles generally do not release cyanide ions, the cyanohydrins do and are thus rather toxic. Bonding The cyanide ion is isoelectronic with carbon monoxide a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only extant member. Anatomically moder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Cyanide
Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an industrial scale and is a highly valued precursor to many chemical compounds ranging from polymers to pharmaceuticals. Large-scale applications are for the production of potassium cyanide and adiponitrile, used in mining and plastics, respectively. It is more toxic than solid cyanide compounds due to its volatile nature. Structure and general properties Hydrogen cyanide is a linear molecule, with a triple bond between carbon and nitrogen. The tautomer of HCN is HNC, hydrogen isocyanide. Hydrogen cyanide is weakly acidic with a p''K''a of 9.2. It partially ionizes in water solution to give the cyanide anion, CN−. A solution of hydrogen cyanide in water, represented as HCN, is called ''hydrocyanic acid''. The salts of the cyanide ani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
