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Threitol
Threitol is a four-carbon sugar alcohol with the molecular formula C4H10O4. It is primarily used as an intermediate in the chemical synthesis of other compounds. It is the diastereomer of erythritol, which is used as a sugar substitute. In living organisms, threitol is found in the edible fungus ''Armillaria mellea''. It serves as a cryoprotectant (antifreeze agent) in the Alaskan beetle '' Upis ceramboides''. See also * Antifreeze protein * Dithiothreitol, a thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ... derivative of threitol References External links * Sugar alcohols Tetroses Tetrols {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sugar Alcohol
Sugar alcohols (also called polyhydric alcohols, polyalcohols, alditols or glycitols) are organic compounds, typically derived from sugars, containing one hydroxyl group (–OH) attached to each carbon atom. They are white, water-soluble solids that can occur naturally or be produced industrially by hydrogenation of sugars. Since they contain multiple –OH groups, they are classified as polyols. Sugar alcohols are used widely in the food industry as thickeners and sweeteners. In commercial foodstuffs, sugar alcohols are commonly used in place of table sugar (sucrose), often in combination with high-intensity artificial sweeteners, in order to offset their low sweetness. Xylitol and sorbitol are popular sugar alcohols in commercial foods. Chemical structure Sugar alcohols have the general formula HOCH2(CHOH)''n''CH2OH. In contrast, sugars have two fewer hydrogen atoms, for example HOCH2(CHOH)''n''CHO or HOCH2(CHOH)''n''−1C(O)CH2OH. The sugar alcohols differ in chain length. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythritol
Erythritol is an organic compound, a four-carbon sugar alcohol (or polyol) with no optical activity, used as a food additive and sugar substitute. It is naturally occurring. It can be made from corn using enzymes and fermentation. Its formula is , or HO(CH2)(CHOH)2(CH2)OH; specifically, one particular stereoisomer with that formula. Erythritol is 60–70% as sweet as sucrose (table sugar). However, erythritol is almost completely noncaloric and does not affect blood sugar or cause tooth decay. Japanese companies pioneered the commercial development of erythritol as a sweetener in the 1990s. History Erythritol was discovered in 1848 by Scottish chemist John Stenhouse and first isolated in 1852. In 1950 it was found in blackstrap molasses that was fermented by yeast, and it became commercialized as a sugar alcohol in the 1990s in Japan. Natural occurrence and production Erythritol occurs naturally in some fruit and fermented foods. It also occurs in human body fluids such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sugar Alcohols
Sugar alcohols (also called polyhydric alcohols, polyalcohols, alditols or glycitols) are organic compounds, typically derived from sugars, containing one hydroxyl group (–OH) attached to each carbon atom. They are white, water-soluble solids that can occur naturally or be produced industrially by hydrogenation of sugars. Since they contain multiple –OH groups, they are classified as polyols. Sugar alcohols are used widely in the food industry as thickeners and sweeteners. In commercial foodstuffs, sugar alcohols are commonly used in place of table sugar ( sucrose), often in combination with high-intensity artificial sweeteners, in order to offset their low sweetness. Xylitol and sorbitol are popular sugar alcohols in commercial foods. Chemical structure Sugar alcohols have the general formula HOCH2(CHOH)''n''CH2OH. In contrast, sugars have two fewer hydrogen atoms, for example HOCH2(CHOH)''n''CHO or HOCH2(CHOH)''n''−1C(O)CH2OH. The sugar alcohols differ in chain lengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diastereomer
In stereochemistry, diastereomers (sometimes called diastereoisomers) are a type of stereoisomer. Diastereomers are defined as non-mirror image, non-identical stereoisomers. Hence, they occur when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent (related) stereocenters and are not mirror images of each other. When two diastereoisomers differ from each other at only one stereocenter, they are epimers. Each stereocenter gives rise to two different configurations and thus typically increases the number of stereoisomers by a factor of two. Diastereomers differ from enantiomers in that the latter are pairs of stereoisomers that differ in all stereocenters and are therefore mirror images of one another. Enantiomers of a compound with more than one stereocenter are also diastereomers of the other stereoisomers of that compound that are not their mirror image (that is, excluding the opposing enantiomer). Diastereomers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edible Fungus
Edible mushrooms are the fleshy and edible fruit bodies of several species of macrofungi (fungi which bear fruiting structures that are large enough to be seen with the naked eye). They can appear either below ground (hypogeous) or above ground (epigeous) where they may be picked by hand. Edibility may be defined by criteria that include absence of poisonous effects on humans and desirable taste and aroma. Edible mushrooms are consumed for their nutritional and culinary value. Mushrooms, especially dried shiitake, are sources of umami flavor. Edible mushrooms include many fungal species that are either harvested wild or cultivated. Easily cultivated and common wild mushrooms are often available in markets, and those that are more difficult to obtain (such as the prized truffle, matsutake, and morel) may be collected on a smaller scale by private gatherers. Some preparations may render certain poisonous mushrooms fit for consumption. Before assuming that any wild mushroom is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armillaria Mellea
''Armillaria mellea'', commonly known as honey fungus, is a basidiomycete fungus in the genus ''Armillaria''. It is a plant pathogen and part of a cryptic species complex of closely related and morphologically similar species. It causes Armillaria root rot in many plant species and produces mushrooms around the base of trees it has infected. The symptoms of infection appear in the crowns of infected trees as discoloured foliage, reduced growth, dieback of the branches and death. The mushrooms are edible but some people may be intolerant to them. This species is capable of producing light via bioluminescence in its mycelium. ''Armillaria mellea'' is widely distributed in temperate regions of the Northern Hemisphere. The fruit body or mushroom, commonly known as stump mushroom, stumpie, honey mushroom, pipinky or pinky, grows typically on hardwoods but may be found around and on other living and dead wood or in open areas. Taxonomy The species was originally named ''Agaricus m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upis Ceramboides
''Upis ceramboides'' is a species of beetle, one of many wood-living insects that benefit from forest fires. It often occurs in quantities below the bark on the fire-damaged birches, but can sometimes be seen on other deciduous trees such as willow and aspen. The larvae thrive in the inner bark which is rich in mycelia, and in the sapwood. They develop into pupae during the summer months under the bark, and they develop over two or three years. The following spring they reproduce themselves. It has over the years have disappeared from southern Sweden and is now only locally in the Norrland coast (Västerbotten and Norrbotten) as well as Canada and Alaska. The reason for the species' decline is probably the lack of fire-damaged forests and birch, and the modern forestry practices. ''Upis ceramboides'' is considered "vulnerable" in terms of species survival. In Vindeln municipality it is called ', because it occurs indoors when burning firewood in winter. The species' survival at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Biological Chemistry
The ''Journal of Biological Chemistry'' (''JBC'') is a weekly peer-reviewed scientific journal that was established in 1905., jbc.org Since 1925, it is published by the American Society for Biochemistry and Molecular Biology. It covers research in areas of biochemistry and molecular biology. The editor is Alex Toker. As of January 2021, the journal is fully open access. In press articles are available free on its website immediately after acceptance. Editors The following individuals have served as editors of the journal: * 1906–1909: John Jacob Abel and Christian Archibald Herter * 1909–1910: Christian Archibald Herter * 1910–1914: Alfred Newton Richards * 1914–1925: Donald D. Van Slyke * 1925–1936: Stanley R. Benedict. After Benedict died, John T. Edsall served as temporary editor until the next editor was appointed. * 1937–1958: Rudolph J. Anderson * 1958–1967: John T. Edsall * 1968–1971: William Howard Stein * 1971–2011: Herbert Tabor * 2011–201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antifreeze Protein
Antifreeze proteins (AFPs) or ice structuring proteins refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water. AFPs bind to small ice crystals to inhibit the growth and recrystallization of ice that would otherwise be fatal. There is also increasing evidence that AFPs interact with mammalian cell membranes to protect them from cold damage. This work suggests the involvement of AFPs in cold acclimatization. Non-colligative properties Unlike the widely used automotive antifreeze, ethylene glycol, AFPs do not lower freezing point in proportion to concentration. Rather, they work in a non colligative manner. This phenomenon allows them to act as an antifreeze at concentrations 1/300th to 1/500th of those of other dissolved solutes. Their low concentration minimizes their effect on osmotic pressure. The unusual properties of AFPs are attributed to their selective a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiothreitol
Dithiothreitol (DTT) is the common name for a small-molecule redox reagent also known as Cleland's reagent, after W. Wallace Cleland. DTT's formula is C4H10O2S2 and the chemical structure of one of its enantiomers in its reduced form is shown on the right; its oxidized form is a disulfide bonded 6-membered ring (shown below). The reagent is commonly used in its racemic form, as both enantiomers are reactive. Its name derives from the four-carbon sugar, threose. DTT has an epimeric ('sister') compound, dithioerythritol (DTE). Reducing agent DTT is a reducing agent; once oxidized, it forms a stable six-membered ring with an internal disulfide bond. It has a redox potential of −0.33 V at pH 7. The reduction of a typical disulfide bond proceeds by two sequential thiol-disulfide exchange reactions and is illustrated below. The reduction usually does not stop at the mixed-disulfide species because the second thiol of DTT has a high propensity to close the ring, forming oxidized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiol
In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols (that is, sulfur takes the place of oxygen in the hydroxyl () group of an alcohol), and the word is a blend of "''thio-''" with "alcohol". Many thiols have strong odors resembling that of garlic or rotten eggs. Thiols are used as odorants to assist in the detection of natural gas (which in pure form is odorless), and the "smell of natural gas" is due to the smell of the thiol used as the odorant. Thiols are sometimes referred to as mercaptans () or mercapto compounds, a term introduced in 1832 by William Christopher Zeise and is derived from the Latin ('capturing mercury')''Oxford American Dictionaries'' ( Mac OS X Leopard). because the thiolate group () bonds very stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetroses
A tetrose is a monosaccharide with 4 carbon atoms. They have either an aldehyde functional group in position 1 (aldotetroses) or a ketone functional group in position 2 (ketotetroses). File:DErythrose Fischer.svg , D-Erythrose File:DThreose Fischer.svg , D-Threose File:DErythrulose Fischer.svg , D-Erythrulose The aldotetroses have two chiral centers (asymmetric carbon atoms) and so 4 different stereoisomers are possible. There are two naturally occurring stereoisomers, the enantiomers of erythrose and threose having the D configuration but not the L enantiomers. The ketotetroses have one chiral center and, therefore, two possible stereoisomers: erythrulose (L- and D-form). Again, only the D enantiomer is naturally occurring. Biological Functions There are a few known ways that tetrose sugars are used in nature. Some are seen in metabolic pathways and others are known to affect certain enzymes. Intermediates in the Pentose Phosphate Pathway One of the metabolic pathways ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
