"On the basis of [our] observations, we propose that the widespread adoption and use of the disaccharide trehalose in the human diet has played a significant role in the emergence of these epidemic and hypervirulent strains," the authors write in a paper published yesterday in the journal Nature.
|
|
Trehalose is a disaccharide formed by a bond between two α-glucose units. Two other isomers are not found in nature. It is found in nature as a disaccharide and also as a monomer in some polymers.
|
|
Xylobiose is a disaccharide of xylose monomers with a beta-1,4-bond between them.
|
|
The reverse reaction in which the glycosidic bond of a disaccharide is broken into two monosaccharides is termed hydrolysis. The best-known disaccharide is sucrose or ordinary sugar, which consists of a glucose molecule and a fructose molecule joined together. Another important disaccharide is lactose found in milk, consisting of a glucose molecule and a galactose molecule. Lactose may be hydrolysed by lactase, and deficiency in this enzyme results in lactose intolerance.
|
|
The advantage of “arming” and “disarming” glycosyl donors lies in their synthetic use. By disarming the glycosyl, a selective coupling can be achieved. The disarmed portion of the disaccharide can then be armed through selective deprotection. The disaccharide can then be coupled to a disarmed sugar.
|
|
3α-Mannobiose is a disaccharide composed of two mannose molecules connected by α(1→3) glycosidic bond.
|
|
Disaccharides consist of two monosaccharides and may be either reducing or nonreducing. Even a reducing disaccharide will only have one reducing end, as disaccharides are held together by glycosidic bonds, which consist of at least one anomeric carbon. With one anomeric carbon unable to convert to the open-chain form, only the free anomeric carbon is available to reduce another compound, and it is called the reducing end of the disaccharide. A nonreducing disaccharide is that which has both anomeric carbons tied up in the glycosidic bond.
|
|
In most cases, it is equivalent to alpha-glucosidase, but the term "maltase" emphasizes the disaccharide nature of the substrate from which glucose is cleaved, and "alpha-glucosidase" emphasizes the bond, whether the substrate is a disaccharide or polysaccharide. Vampire bats are the only vertebrates known to not exhibit intestinal maltase activity.
|
|
Sucrose, a disaccharide formed from condensation of a molecule of glucose and a molecule of fructose A disaccharide (also called a double sugar or bivoseBiose on www.merriam-webster.org) is the sugar formed when two monosaccharides (simple sugars) are joined by glycosidic linkage. Like monosaccharides, disaccharides are soluble in water. Three common examples are sucrose, lactose, and maltose.
|
|
There are two types of strontium saccharide: one at low temperature, the strontium monosaccharide; and the second at high temperature, the strontium disaccharide.
|
|
2α-Mannobiose is a disaccharide. It is formed by a condensation reaction, when two mannose molecules react together, in the formation of a glycosidic bond.
|
|
There is no reported total synthesis of chloroeremomycin, although there are several total syntheses of vancomycin. The structures of vancomycin and chloroeremomycin are very similar, differing only in the glycosylation sites. Vancomycin is glycosylated at aa4 with a (2-beta1)-Glc- vancosamine disaccharide. As mentioned above, chloroeremomycin is glycosylated at aa4 with a (2-beta1)-Glc-epivancosamine disaccharide and at aa6 with a beta1-epivancosamine saccharide.
|
|
All three human trefoil factors are lectins that interact specifically with the disaccharide GlcNAc-α-1,4-Gal. This disaccharide is an unusual glycotope that is only known to exist on the large, heavily glycosylated, mucins in the mucosa. By cross- linking mucins through the bivalent binding of this glycotope, the trefoil factors are then able to reversible modulate the thickness and viscosity of the mucus.
|
|
All three human trefoil factors are lectins that interact specifically with the disaccharide GlcNAc-α-1,4-Gal. This disaccharide is an unusual glycotope that is only known to exist on the large, heavily glycosylated, mucins in the mucosa. By cross-linking mucins through the bivalent binding of this glycotope, the trefoil factors are then able to reversible modulate the thickness and viscosity of the mucus.
|
|
All human trefoil factors are lectins that interact specifically with the disaccharide GlcNAc-α-1,4-Gal. This disaccharide is an unusual glycotope that is only known to exist on the large, heavily glycosylated, mucins in the mucosa. By cross-linking mucins through the bivalent binding of this glycotope, the trefoil factors are then able to reversible modulate the thickness and viscosity of the mucus.
|
|
Vicianin is a cyanogenic disaccharide. The enzyme vicianin beta-glucosidase uses (R)-vicianin and H2O to produce mandelonitrile and vicianose. It is found in seeds of Vicia angustifolia.
|
|
Sambubiose is a disaccharide. It is the β-D-xylosyl-(1→2)-β-D-glucose. Sambubiose is a component of some glycoside pigments. The fruits of Viburnum dentatum appear blue.
|
|
Robinose is a disaccharide composed of 6″-O-α-rhamnopyranosyl-β- galactopyranoside. The sugar can be found in Acalypha hispida. Robinin is a kaempferol-3-O-robinoside-7-O-rhamnoside.
|
|
Kojibiose is a disaccharide. It is a product of the caramelization of glucose. It is also present in honey (approx. 3%). Kojibiose has a mild sweet taste, but low calorie count.
|
|
These include lactose, the predominant sugar in milk, which is a glucose-galactose disaccharide, and sucrose, another disaccharide which is composed of glucose and fructose. Glucose is also added onto certain proteins and lipids in a process called glycosylation. This is often critical for their functioning. The enzymes that join glucose to other molecules usually use phosphorylated glucose to power the formation of the new bond by coupling it with the breaking of the glucose-phosphate bond.
|
|
Glycosaminoglycans vary greatly in molecular mass, disaccharide construction, and sulfation. This is because GAG synthesis is not template driven like proteins or nucleic acids, but constantly altered by processing enzymes. GAGs are classified into four groups based on core disaccharide structures. Heparin/heparan sulfate (HSGAGs) and chondroitin sulfate/dermatan sulfate (CSGAGs) are synthesized in the Golgi apparatus, where protein cores made in the rough endoplasmic reticulum are post-translationally modified with O-linked glycosylations by glycosyltransferases forming proteoglycans.
|
|
Unlike the Maillard reaction, caramelization is pyrolytic, as opposed to being a reaction with amino acids. When caramelization involves the disaccharide sucrose, it is broken down into the monosaccharides fructose and glucose.
|
|
Maltose, another common disaccharide, is condensed from two glucose molecules. The dehydration reaction that bonds monosaccharides into disaccharides (and also bonds monosaccharides into more complex polysaccharides) forms what are called glycosidic bonds.
|
|
Sophorose is a disaccharide. It is a glucose-derived di-saccharide with an unusual β-1,2 bond. It is a component of sophorolipids. It is a product of the caramelization of glucose.
|
|
The minimal lipopolysaccharide required for growth in E. coli is Kdo2-Lipid A, a hexa-acylated disaccharide of glucosamine that is glycosylated with two 3-deoxy-D-manno-octulosonic acid (Kdo) residues.
|
|
A disaccharide is formed when a dehydration reaction joins two monosaccharides. Another type of macromolecules are lipids. Lipids are hydrocarbons that do not form polymers. Fats are constructed from glycerol and fatty acids.
|
|
Rutinose is the disaccharide also known as 6-O-α-L-rhamnosyl-D-glucose (C12H22O10) that is present in some flavonoid glycosides. It is prepared from rutin by hydrolysis with the enzyme rhamnodiastase.
|
|
The formation of a disaccharide molecule from two monosaccharide molecules proceeds by displacing a hydroxyl radical from one molecule and a hydrogen nucleus (a proton) from the other, so that the now vacant bonds on the monosaccharides join the two monomers together. The vacant bonds on the hydroxyl radical and the proton unite in their turn, forming a molecule of water, that then goes free. Because of the removal of the water molecule from the product, the term of convenience for such a process is "dehydration reaction" (also "condensation reaction" or "dehydration synthesis"). For example, milk sugar (lactose) is a disaccharide made by condensation of one molecule of each of the monosaccharides glucose and galactose, whereas the disaccharide sucrose in sugar cane and sugar beet, is a condensation product of glucose and fructose.
|
|
Lactose is a disaccharide. It is a sugar composed of galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by weight). The name comes from ' (gen.
|
|
Sucrose is common sugar. It is a disaccharide, a molecule composed of two monosaccharides: glucose and fructose. Sucrose is produced naturally in plants, from which table sugar is refined. It has the molecular formula C12H22O11.
|
|
Sucrase is an enzyme that breaks down the disaccharide sucrose, commonly known as table sugar, cane sugar, or beet sugar. Sucrose digestion yields the sugars fructose and glucose which are readily absorbed by the small intestine.
|
|
In enzymology, a pectate disaccharide-lyase () is an enzyme that catalyzes the chemical reaction :Eliminative cleavage of 4-(4-deoxy-alpha-D- galact-4-enuronosyl)-D-galacturonate from the reducing end of pectate, i.e. de-esterified pectin This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. The systematic name of this enzyme class is (1->4)-alpha-D-galacturonan reducing-end-disaccharide- lyase. Other names in common use include pectate exo-lyase, exopectic acid transeliminase, exopectate lyase, exopolygalacturonic acid-trans-eliminase, PATE, exo-PATE, and exo-PGL.
|
|
Maltose is a disaccharide: the carbohydrates are generally divided into monosaccharides, oligosaccharides, and polysaccharides depending on the number of sugar subunits. Maltose, with two sugar units, is an oligosaccharide, specifically a disaccharide, because it consists of two glucose molecules. Glucose is a hexose: a monosaccharide containing six carbon atoms. The two glucose units are in the pyranose form and are joined by an O-glycosidic bond, with the first carbon (C1) of the first glucose linked to the fourth carbon (C4) of the second glucose, indicated as (1→4).
|
|
Keratan sulfate may modify core proteins through N-linked glycosylation or O-linked glycosylation of the proteoglycan. The fourth class of GAG, hyaluronic acid is synthesized by integral membrane synthases which immediately secrete the dynamically elongated disaccharide chain.
|
|
The purpose of the reaction is to remove the residues from disaccharide cellobiose to produce glucose during the hydrolysis of biomass. Depending on the what the enzyme is reacting with the end product will be one or two glucose molecules.
|
|
Lactobionic acid (4-O-β-galactopyranosyl-D-gluconic acid) is a sugar acid. It is a disaccharide formed from gluconic acid and galactose. It can be formed by oxidation of lactose. The carboxylate anion of lactobionic acid is known as lactobionate.
|
|
256-65 the pioneering synthesis of C-disaccharides,V. C. Xin, J.-M. Mallet, P. Sinaÿ, « An expeditious synthesis of C-disaccharide using a temporary silaketal connection », Journal of the Chemical Society, Chemical Communications, 1993, 10, p. 864 electrochemical glycosylationC.
|
|
Osteoadherin, fibromodulin, and PRELP are core proteins found in bone and cartilage, that are modified by N-linked KS chains. Osteoadherin and Fibromodulin linked KS chains are shorter than those found in the cornea, typically 8-9 disaccharide units in length. Whereas corneal KSI is composed of a number of domains showing variable degrees of sulphation the longest of which may be 8-32 disaccharide units in length. The non-reducing terminal of Fibromodulin KS is more similar in structure to the non-reducing terminal of a KSII type keratan sulphate rather than to corneal KSI.
|
|
Further biochemical studies elucidated specificity and localization of human Sulfs 1 and 2. Sulf1 and 2 hydrophilic domains associate with the cell membrane components through electrostatic interactions and not by integration with into the lipid bilayer. In addition to cell membrane association, Sulfs also secreted freely into the media, which contrasts the findings with QSulf1 and 2. Biochemical analysis of HSPGs in Sulf 1 and 2 knockout MEFS reveal enzyme specificities to disulfated and, primarily, trisulfated 6S disaccharide units UA-GlcNS(6S) and UA(2S)-GlcNS(6S) within the HS chain, with specific exclusion of monosulfated disaccharide units.
|
|
Laminaribiose C12H22O11 is a disaccharide which is used notably in the agricultural field and as an antiseptic. It is in general obtained by hydrolysis or by acetolysis of natural polysaccharides of plant origin. It is also a product of the caramelization of glucose.
|
|
Rutin, also called rutoside, quercetin-3-O-rutinoside and sophorin, is the glycoside combining the flavonol quercetin and the disaccharide rutinose (α-L- rhamnopyranosyl-(1→6)-β-D-glucopyranose). It is a citrus flavonoid found in a wide variety of plants including citrus.
|
|
The Sulfotransferase domain of this enzyme is highly similar to the same domain of heparan sulfate D-glucosaminyl 3-O-sulfotransferase 3A1 and these two enzymes sulfate an identical disaccharide. This gene is widely expressed, with the most abundant expression in liver and placenta.
|
|
Turanose is a reducing disaccharide. The -isomer is naturally occurring. Its systematic name is α--glucopyranosyl-(1→3)-α--fructofuranose. It is an analog of sucrose not metabolized by higher plants, but rather acquired through the action of sucrose transporters for intracellular carbohydrate signaling.
|
|
The sulfotransferase domain of this enzyme is highly similar to the same domain of heparan sulfate D-glucosaminyl 3-O-sulfotransferase 3A1, and these two enzymes sulfate an identical disaccharide. This gene is widely expressed, with the most abundant expression in the liver and placenta.
|
|
Glycosaminoglycans are long, unbranched polysaccharides (relatively complex carbohydrates) consisting of repeating disaccharide units. Fibrocartilage does not have a surrounding perichondrium. Perichondrium surrounds the cartilage of developing bone; it has a layer of dense, irregular connective tissue and functions in the growth and repair of cartilage.
|
|
Lipid II is the final intermediate in peptidoglycan synthesis. It is formed when the MurG transferase catalyzes addition of N-acetylglucosamine (GlcNAc) to Lipid I, resulting in a complete disaccharide-pentapeptide monomer with a bactoprenol-pyrophosphate anchor. This occurs on the inside of the cytoplasmic membrane, where the bactoprenol chain is embedded in the inner leaflet of the bilayer. Lipid II is then transported across the membrane by a flippase, to expose the disaccharide-pentapeptide monomer, which is the pentapeptide stem consisting of L-Ala-γ-D-Glu-m-DAP-D-Ala-D-Ala between GlcNAc and N-acetylmuramic acid (MurNAc), for polymerization and cross-linking into peptidoglycan.
|
|
Breaking down a protein into amino acids, or a triglyceride into fatty acids, or a disaccharide into monosaccharides are all hydrolysis or catabolic reactions. Second, oxidation reactions involve the removal of hydrogens and electrons from an organic molecule."Lehninger's Principles of Biochemistry", 4th edition, pp. 616, 2004.
|
|
Galactose is a monosaccharide. When combined with glucose (monosaccharide), through a condensation reaction, the result is the disaccharide lactose. The hydrolysis of lactose to glucose and galactose is catalyzed by the enzymes lactase and β-galactosidase. The latter is produced by the lac operon in Escherichia coli.
|
|
In enzymology, an inulin fructotransferase (DFA-III-forming) () is an enzyme that catalyzes the chemical reaction :Produces alpha-D-fructofuranose beta-D- fructofuranose 1,2':2,3'-dianhydride (DFA III) by successively eliminating the diminishing (2->1)-beta-D-fructan (inulin) chain from the terminal D-fructosyl-D-fructosyl disaccharide.
|
|
Verbascoside is a caffeoyl phenylethanoid glycoside in which the phenylpropanoid caffeic acid and the phenylethanoid hydroxytyrosol form an ester and an ether bond respectively, to the rhamnose part of a disaccharide, namely β-(3′,4′-dihydroxyphenyl)ethyl-O-α-L- rhamnopyranosyl(1→3)-β-D-(4-O-caffeoyl)-glucopyranoside.
|
|
Typical lipid A molecules are disaccharides of glucosamine, which are derivatized with as many as seven fatty-acyl chains. The minimal lipopolysaccharide required for growth in E. coli is Kdo2-Lipid A, a hexa-acylated disaccharide of glucosamine that is glycosylated with two 3-deoxy-D-manno-octulosonic acid (Kdo) residues.
|
|
Narirutin is a flavanone-7-O-glycoside, consisting of the flavanone naringenin bonded with the disaccharide rutinose. It is found in orange juice.Interferences with naringin and neohesperidin analysis by high performance liquid chromatography. Widmer W.W and Martin S.F., 1993 Ultraviolet 280 nm chromatogram after UHPLC separation of commercial orange juice.
|
|
Isomaltulose is a disaccharide carbohydrate composed of glucose and fructose. The glucose and fructose are linked by an alpha-1,6-glycosidic bond (chemical name: 6-0-α-D-glucopyranosyl-D-fructose). Isomaltulose is present in honey and sugarcane extracts. It tastes similar to sucrose (table sugar) with half the sweetness.
|
|
The joining of two aldehyde sugars to form a disaccharide removes the −OH from the carboxy group at the aldehyde end of one sugar. The creation of a peptide bond to link two amino acids to make a protein removes the −OH from the carboxy group of one amino acid.
|
|
Glycoside hydrolase family 37 CAZY GH_37 comprises enzymes with only one known activity; trehalase (). Trehalase is the enzyme responsible for the degradation of the disaccharide alpha,alpha-trehalose yielding two glucose subunits. It is an enzyme found in a wide variety of organisms and whose sequence has been highly conserved throughout evolution.
|
|
Cellobiose is a disaccharide with the formula (C6H7(OH)4O)2O. It is classified as a reducing sugar. In terms of its chemical structure, it is derived from the condensation of a pair β-glucose molecules forging a β(1→4) bond. It can be hydrolyzed to glucose enzymatically or with acid.
|
|
CRC Handbook of Enthalpy Data of Polymer-Solvent Systems. CRC Press, 2006. Google Books result: ), lower than many other sugar alcohols, in particular, xylitol and erythritol. Isomalt is manufactured in a two-stage process in which sucrose is first transformed into isomaltulose, a reducing disaccharide (6-O-α-D-glucopyranosido-D-fructose).
|
|
Kappa-carrageenan has one sulfate group per disaccharide, iota-carrageenan has two, and lambda- carrageenan has three. Gelatinous extracts of the Chondrus crispus (Irish moss) seaweed have been used as food additives since approximately the fifteenth century.FAO Agar and Carrageenan Manual. Food and Agriculture Organization of the United Nations (1965-01-01).
|
|
Most of the fructose and galactose travel to the liver, where they can be converted to glucose. Some simple carbohydrates have their own enzymatic oxidation pathways, as do only a few of the more complex carbohydrates. The disaccharide lactose, for instance, requires the enzyme lactase to be broken into its monosaccharide components, glucose and galactose.
|
|
Fudge being cooled and shaped on a marble slab In forming a fondant, it is not easy to keep all vibrations and seed crystals from causing rapid crystallization into large crystals. Consequently, milkfat and corn syrup are often added. Corn syrup contains glucose, fructose (monosaccharides), and maltose (disaccharide). These sugars interact with sucrose molecules.
|
|
Neoeriocitrin is a 7-O-glycoside of the flavanone eriodictyol and the disaccharide neohesperidose (Alpha-L-rhamnopyranosyl-(1->2)-beta-D- glucopyranose). Note that the 'neo' in the name in this case does not refer to the position of the B-ring (which is not in a neo position), but refer to the glycosyl moiety.
|
|
Like the chondroitin sulfate proteoglycans, keratan sulfate proteoglycan (KSPG) production is up regulated in reactive astrocytes as part of glial scar formation. KSPGs have also been shown to inhibit neurite outgrowth extension, limiting nerve regeneration. Keratan sulfate, also called keratosulfate, is formed from repeating disaccharide galactose units and N-acetylglucosamines. It is also 6-sulfated.
|
|
The word galactose was coined by Charles Weissman in the mid 19th century and is derived from Greek galaktos (milk) and the generic chemical suffix for sugars -ose. The etymology is comparable to that of the word lactose in that both contain roots meaning "milk sugar". Lactose is a disaccharide of galactose plus glucose.
|
|
The majority of oligosaccharides found in IMO consist of three to six monosaccharide (glucose) units linked together. However, disaccharides, as well as longer polysaccharides (up to nine glucose units), are also present. The disaccharide fraction of IMO consists mainly of α(1,6)-linked isomaltose, while maltotriose, panose, and isomaltotriose make up the trisaccharide fraction.
|
|
The best-known disaccharide is sucrose (table sugar). Hydrolysis of sucrose yields glucose and fructose. Invertase is a sucrase used industrially for the hydrolysis of sucrose to so-called invert sugar. Lactase is essential for digestive hydrolysis of lactose in milk; many adult humans do not produce lactase and cannot digest the lactose in milk.
|
|
N-Acetyllactosamine (LacNAc) is a nitrogen-containing disaccharide. The N-acetyllactosamine is a component of many glycoproteins and functions as a carbohydrate antigen that is thought to play roles in normal cellular recognition as well as in malignant transformation and metastasis. It is also found in the structure of human milk oligosaccharides and has prebiotic effects.
|
|
Sucrose is another ingredient utilized in most aerated confections. It is a disaccharide that consists of one glucose and fructose molecule. This sugar provides sweetness and bulk to the marshmallow, while simultaneously setting the foam to a firm consistency as it cools. Sucrose, and sugars in general, impair the ability of a foam to form, but improve foam stability.
|
|
Gentiobiose is a disaccharide composed of two units of D-glucose joined with a β(1->6) linkage. It is a white crystalline solid that is soluble in water or hot methanol. Gentiobiose is incorporated into the chemical structure of crocin, the chemical compound that gives saffron its color. It is a product of the caramelization of glucose.
|
|
The cream of tartar also acts as a catalyst affecting the sugar structure. Sucrose is a disaccharide made up of glucose and fructose. Cream of tartar inverts the sugar during the baking process, meaning the molecule is split into two parts containing glucose and fructose. This prevents the sugar from recrystallizing and giving the meringue a gritty, undesirable texture.
|
|
Sucrose which is disaccharide is usually used as a sweetening agent. Lactose which is sugar present in milk will cause freezing point depression. Thus, on freezing some water will remain unfrozen and will not give a hard texture. Too much lactose will result in a non ideal texture because of either excessive freezing point depression or lactose crystallization.
|
|
Eriocitrin (eriodictyol glycoside) is a flavanone-7-O-glycoside between the flavanone eriodictyol and the disaccharide rutinose. It is commonly found in lemons. It is colloquially called lemon flavonoid or a citrus flavonoid, one of the plant pigments that bring color to fruit and flowers. This antioxidant also predominates (38% in 1 study) in Peppermint infusions.
|
|
Maltitol is a disaccharide produced by hydrogenation of maltose obtained from starch. Maltitol syrup, a hydrogenated starch hydrolysate, is created by hydrogenating corn syrup, a mixture of carbohydrates produced from the hydrolysis of starch. This product contains between 50% and 80% maltitol by weight. The remainder is mostly sorbitol, with a small quantity of other sugar-related substances.
|
|
ApoCIII is a relatively small protein containing 79 amino acids that can be glycosylated at threonine-74. The most abundant glycoforms are characterized by an O-linked disaccharide galactose linked to N-acetylgalactosamine (Gal- GalNAc), further modified with up to 2 sialic acid residues. Less abundant glycoforms are characterized by more complex and fucosylated glycan moieties.
|
|
Isomaltose is a disaccharide similar to maltose, but with a α-(1-6)-linkage instead of the α-(1-4)-linkage. Both of the sugars are glucose, which is a pyranose sugar. Isomaltose is a reducing sugar. Isomaltose is produced when high maltose syrup is treated with the enzyme transglucosidase (TG) and is one of the major components in the mixture isomaltooligosaccharide.
|
|
The cell wall is distinctive, with a predominance of mesodiaminopimelic acid in the murein wall and many repetitions of arabinogalactan, as well as corynemycolic acid (a mycolic acid with 22 to 26 carbon atoms), bound by disaccharide bonds called L-Rhap-(1 → 4)--D-GlcNAc-phosphate. These form a complex commonly seen in Corynebacterium species: the mycolyl-AG–peptidoglican (mAGP).
|
|
Allolactose is a disaccharide similar to lactose. It consists of the monosaccharides D-galactose and D-glucose linked through a β1-6 glycosidic linkage instead of the β1-4 linkage of lactose. It may arise from the occasional transglycosylation of lactose by β-galactosidase. It is an inducer of the lac operon in Escherichia coli and many other enteric bacteria.
|
|
Stage two occurs in the cytoplasmic membrane. It is in the membrane where a lipid carrier called bactoprenol carries peptidoglycan precursors through the cell membrane. Bactoprenol will attack the UDP-MurNAc penta, creating a PP-MurNac penta, which is now a lipid. UDP-GlcNAc is then transported to MurNAc, creating Lipid-PP-MurNAc penta-GlcNAc, a disaccharide, also a precursor to peptidoglycan.
|
|
Breaking apart a double sugar into its two simple sugars is accomplished by hydrolysis with the help of a type of enzyme called a disaccharidase. As building the larger sugar ejects a water molecule, breaking it down consumes a water molecule. These reactions are vital in metabolism. Each disaccharide is broken down with the help of a corresponding disaccharidase (sucrase, lactase, and maltase).
|
|
Isomalto-oligosaccharides are a normal part of the human diet and occur naturally in fermented foods, such as fermented sourdough breads and kimchi. The disaccharide isomaltose is also present in rice miso, soy sauce, and sake.Hondo, S. & Mochizuki, T., Free Sugars in Miso. Nipon Shokuhin Kogyo Gakkaishi 26(11), (1979) 469-472Nishino, R.; Ozawa, Y.; Yasuda, A.; Sakasai, T. 1981.
|
|
Levan is synthesized in archaea, fungi, bacteria, and a limited number of plant species. Fructans such as levan are synthesized from sucrose, a disaccharide sugar containing glucose and fructose. In plants, the vacuole is where fructan production occurs. Sucrose:sucrose/fructan 6-fructosyltransferase is the fructosyltransferase in the vacuole which creates the beta 2,6 linkages to form the linear form of levan.
|
|
The principal soluble carbohydrates of mature soybeans are the disaccharide sucrose (range 2.5–8.2%), the trisaccharide raffinose (0.1–1.0%) composed of one sucrose molecule connected to one molecule of galactose, and the tetrasaccharide stachyose (1.4 to 4.1%) composed of one sucrose connected to two molecules of galactose. While the oligosaccharides raffinose and stachyose protect the viability of the soybean seed from desiccation (see above section on physical characteristics) they are not digestible sugars, so contribute to flatulence and abdominal discomfort in humans and other monogastric animals, comparable to the disaccharide trehalose. Undigested oligosaccharides are broken down in the intestine by native microbes, producing gases such as carbon dioxide, hydrogen, and methane. Since soluble soy carbohydrates are found in the whey and are broken down during fermentation, soy concentrate, soy protein isolates, tofu, soy sauce, and sprouted soybeans are without flatus activity.
|
|
Nigerose, also known as sakebiose, is an unfermentable sugar obtained by partial hydrolysis of nigeran, a polysaccharide found in black mold, but is also readily extracted from the dextrans found in rice molds and many other fermenting microorganisms, such as L. mesenteroides. It is a disaccharide made of two glucose residues, connected with a 1->3 link. It is a product of the caramelization of glucose.
|
|
Configuration of TCT within the cell wall of a bacteriumThe DAP residue is responsible for directly bonding to the D-alanine peptide of another PGN molecule, thus aiding TCT's attachment within the cell wall.Analogs of TCT. LacAEDapA retains the peptide chain of TCT along with toxicity despite the lack of disaccharide. LacAEαApmA loses the diamino group of TCT along with a significant level of toxicity.
|
|
Confections are defined by the presence of sweeteners. These are usually sugars, but it is possible to buy sugar-free candies, such as sugar-free peppermints. The most common sweetener for home cooking is table sugar, which is chemically a disaccharide containing both glucose and fructose. Hydrolysis of sucrose gives a mixture called invert sugar, which is sweeter and is also a common commercial ingredient.
|
|
The toxicity of prunasin is based in its degradation products: (R)-prunasin is hydrolyzed to form benzaldehyde and hydrogen cyanide, which causes toxicity. Plants containing prunasin may therefore be toxic to animals, particularly ruminants. To degrade amygdalin to prunasin, amygdalin beta-glucosidase hydrolyzes the disaccharide to produce (R)-prunasin and D-glucose. Then, prunasin beta-glucosidase uses (R)-prunasin and water to produce D-glucose and mandelonitrile.
|
|
This gene, which is one of the largest in the human genome, encodes a member of the N-acetylglucosaminyltransferase gene family. The exact function of LARGE, a golgi protein, remains uncertain. It encodes a glycosyltransferase which participates in glycosylation of alpha- dystroglycan, and may carry out the synthesis of glycoprotein and glycosphingolipid sugar chains. It may also be involved in the addition of a repeated disaccharide unit.
|
|
29% - 54% of fructose is converted in liver to glucose, and about a quarter of fructose is converted to lactate. 15% - 18% is converted to glycogen. Glucose and lactate are then used normally as energy to fuel cells all over the body. Fructose is a dietary monosaccharide present naturally in fruits and vegetables, either as free fructose or as part of the disaccharide sucrose, and as its polymer inulin.
|
|
Tn antigen refers to the monosaccharide structure N-acetylgalactosamine (GalNAc) linked to serine or threonine by a glycosidic bond.I. Brockhausen, H. Schachter, P. Stanley, Essentials of Glycobiology, 2nd edition. A. Varki, R. Cummings, J. Esko, Eds, Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 2009. Chapter 9, O-GalNAc Glycans Addition of an additional galactose monosaccharide creates a disaccharide antigen: the Thomsen-Friedenreich antigen (Gal(b1-3)GalNAc).
|
|
Emamectin, like other avermectins, is a hydrophobic 16-membered macrocyclic lactone. Emamectin differs from avermectins B1a and B1b by the presence of a hydroxyl group at the 4”-epimethylamino group rather than the 4”-position. Avermectins are pentacyclic polyketide-derived compounds linked to a disaccharide of the methylated deoxysugar oleandrose. The determination of the active-site for avermectins is difficult due to poor solubility and lipophilicity of these compounds.
|
|
Lipid II is a precursor molecule in the synthesis of the cell wall of bacteria. It is a peptidoglycan, which is amphipathic and named for its bactoprenol hydrocarbon chain, which acts as a lipid anchor, embedding itself in the bacterial cell membrane. Lipid II must translocate across the cell membrane to deliver and incorporate its disaccharide-pentapeptide "building block" into the peptidoglycan mesh. Lipid II is the target of several antibiotics.
|
|
Disaccharidases are glycoside hydrolases, enzymes that break down certain types of sugars called disaccharides into simpler sugars called monosaccharides. In the human body, disaccharidases are made mostly in an area of the small intestine's wall called the brush border, making them members of the group of "brush border enzymes". A genetic defect in one of these enzymes will cause a disaccharide intolerance, such as lactose intolerance or sucrose intolerance.
|
|
Chondroitin sulfate chains are unbranched polysaccharides of variable length containing two alternating monosaccharides: D-glucuronic acid (GlcA) and N-acetyl-D-galactosamine (GalNAc). Some GlcA residues are epimerized into L-iduronic acid (IdoA); the resulting disaccharide is then referred to as dermatan sulfate. Chondroitin sulfate chains are linked to hydroxyl groups on serine residues of certain proteins. Exactly how proteins are selected for attachment of glycosaminoglycans is not understood.
|
|
Naringin is a flavanone-7-O-glycoside between the flavanone naringenin and the disaccharide neohesperidose. The flavonoid naringin occurs naturally in citrus fruits, especially in grapefruit, where naringin is responsible for the fruit's bitter taste. In commercial grapefruit juice production, the enzyme naringinase can be used to remove the bitterness created by naringin. In humans naringin is metabolized to the aglycone naringenin (not bitter) by naringinase present in the gut.
|
|
Sodium hyaluronate is the sodium salt of hyaluronic acid. It is a glycosaminoglycan and long- chain polymer of disaccharide units of Na-glucuronate-N-acetylglucosamine. It can bind to specific receptors for which it has a high affinity. The polyanionic form, commonly referred to as hyaluronan, is a visco-elastic polymer found in the aqueous and vitreous humour of the eye and in the fluid of articulating joints.
|
|
The hydrolysis of polysaccharides to soluble sugars can be recognized as saccharification. Malt made from barley is used as a source of β-amylase to break down starch into the disaccharide maltose, which can be used by yeast to produce beer. Other amylase enzymes may convert starch to glucose or to oligosaccharides. Cellulose is first hydrolyzed to cellobiose by cellulase and then cellobiose is further hydrolyzed to glucose by beta-glucosidase.
|
|
A simplified representation of a lactose molecule being broken down into glucose (2) and galactose (1) Milk contains several different carbohydrate including lactose, glucose, galactose, and other oligosaccharides. The lactose gives milk its sweet taste and contributes approximately 40% of whole cow's milk's calories. Lactose is a disaccharide composite of two simple sugars, glucose and galactose. Bovine milk averages 4.8% anhydrous lactose, which amounts to about 50% of the total solids of skimmed milk.
|
|
In enzymology, an oligosaccharide-transporting ATPase () is an enzyme that catalyzes the chemical reaction :ATP + H2O + oligosaccharideout \rightleftharpoons ADP + phosphate + oligosaccharidein The 3 substrates of this enzyme are ATP, H2O, and oligosaccharide, whereas its 3 products are ADP, phosphate, and oligosaccharide. This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides to catalyse transmembrane movement of substances. The systematic name of this enzyme class is ATP phosphohydrolase (disaccharide-importing).
|
|
The B3GNT1 gene encodes a β-1,4-glucuronyltransferase, designated B4GAT1, that transfers glucuronic acid towards both α- and β-anomers of xylose. B4GAT1 is the priming enzyme for LARGE, a dual-activity glycosyltransferase that is capable of extending products of B4GAT1. Thus, B4GAT1 is involved in the initiation of the LARGE-dependent repeating disaccharide that is necessary for extracellular matrix protein binding to O-mannosylated α-dystroglycan that is lacking in secondary dystroglycanopathies.
|
|
The selectivity in the reaction is due to the stronger electron withdrawing power of the esters compared to the ethers. A stronger electron withdrawing substituent leads to a greater destabilization of the oxocarbenium ion. This slows this reaction pathway, and allows for disaccharide formation to occur with the benzylated sugar. Other effective electron withdrawing groups that have shown selectivity are halogens and azido groups, while deoxygenation has been proven an effective tool in “arming” sugars.
|
|
The seeds have a sticky coat that helps them adhere to the soil, but they also may be carried downstream by surface wash. However, seeds swept downstream do not survive. The process of curling and uncurling is completely reversible and can be repeated many times. The ability of the plant to do this is attributed to the presence of trehalose, pages 121-122 a disaccharide sugar involved in several mechanisms of cryptobiosis.
|
|
In humans, dietary starches are composed of glucose units arranged in long chains called amylose, a polysaccharide. During digestion, bonds between glucose molecules are broken by salivary and pancreatic amylase, resulting in progressively smaller chains of glucose. This results in simple sugars glucose and maltose (2 glucose molecules) that can be absorbed by the small intestine. Lactase is an enzyme that breaks down the disaccharide lactose to its component parts, glucose and galactose.
|
|
An agarose gel in tray used for gel electrophoresis Agarose is a polysaccharide, generally extracted from certain red seaweed. It is a linear polymer made up of the repeating unit of agarobiose, which is a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose.Agar at lsbu.ac.uk Water Structure and Science Agarose is one of the two principal components of agar, and is purified from agar by removing agar's other component, agaropectin.
|
|
Anidulafungin Discovery of echinocandins stemmed from studies on papulacandins isolated from a strain of Papularia sphaerosperma (Pers.), which were liposaccharide - i.e., fatty acid derivatives of a disaccharide that also blocked the same target, 1,3-β glucan synthase - and had action only on Candida spp. (narrow spectrum). Screening of natural products of fungal fermentation in the 1970s led to the discovery of echinocandins, a new group of antifungals with broad-range activity against Candida spp.
|
|
Lactose, the disaccharide sugar component of all milk, must be cleaved in the small intestine by the enzyme lactase, in order for its constituents, galactose and glucose, to be absorbed. Lactose intolerance is a condition in which people have symptoms due to not enough of the enzyme lactase in the small intestines. Those affected vary in the amount of lactose they can tolerate before symptoms develop. These may include abdominal pain, bloating, diarrhea, gas, and nausea.
|
|
Molecular structure of TCT TCT is a soluble piece of peptidoglycan (PGN) found in the cell wall of all gram-negative bacteria. Like all PGNs, TCT is composed of a disaccharide and a peptide chain. The IUPAC name for TCT is N-acetylglucosaminyl-1,6-anhydro-N- acetylmuramyl-(L)-alanyl-γ-(D)-glutamyl-mesodiaminopimelyl-(D)-alanine. It is classified as a DAP(Diaminopimelic acid)-type PGN due to the third amino group within the chain being a diaminopimelyl peptide.
|
|
Sucrose intolerance (also known as congenital sucrase-isomaltase deficiency (CSID), genetic sucrase-isomaltase deficiency (GSID), or sucrase-isomaltase deficiency) occurs when sucrase is not being secreted in the small intestine. With sucrose intolerance, the result of consuming sucrose is excess gas production and often diarrhea and malabsorption. Lactose intolerance is a related disorder that reflects an individual's inability to hydrolyze the disaccharide lactose. Sucrase is secreted by the tips of the villi of the epithelium in the small intestine.
|
|
While in other anhydrobionts, such as the brine shrimp, this desiccation tolerance is thought to be linked to the production of trehalose, a non-reducing disaccharide (sugar), bdelloids apparently cannot synthesise trehalose. In bdelloids, a major cause of the resistance to desiccation, as well as resistance to ionizing radiation, is a highly efficient mechanism for repairing the DNA double-strand breaks induced by these agents. This repair mechanism likely involves mitotic recombination between homologous DNA regions.
|
|
In turn, disaccharides are mostly degraded by specific glycosidases to glucose. The names of the degrading enzymes are often derived from the particular poly- and disaccharide; inter alia, for the degradation of polysaccharide chains there are amylases (named after amylose, a component of starch), cellulases (named after cellulose), chitinases (named after chitin) and more. Furthermore, for the cleavage of disaccharides, there are maltase, lactase, sucrase, trehalase and others. In humans, about 70 genes are known that code for glycosidases.
|
|
Trehalulose is a disaccharide made up of a molecule of fructose bound to a molecule of glucose. Like isomaltulose, it is a structural isomer of sucrose that is present in small quantities in honey. It makes up 50% of sugars in the honeydew of silverleaf whiteflies and is synthesised from sucrose by some bacteria, such as Protaminombacter rubrum. Because the anomeric carbon of the fructose moiety is not involved in the glycosidic bond, it is a reducing sugar.
|
|
Ingestion of only a few of these cysts is needed to generate infection in another host. Infection with Giardia results in decreased expression of brush border enzymes, morphological changes to the microvillus, increased intestinal permeability, and programmed cell death of small intestinal epithelial cells. Both trophozoites and cysts are contained within the gastrointestinal tract and do not invade beyond it. The attachment of trophozoites causes villus flattening and inhibition of enzymes that break down disaccharide sugars in the intestines.
|
|
Pancreatin contains the pancreatic enzymes trypsin, amylase and lipase. A similar mixture of enzymes is sold as pancrelipase, which contains more active lipase enzyme than does pancreatin. The trypsin found in pancreatin works to hydrolyze proteins into oligopeptides; amylase hydrolyzes starches into oligosaccharides and the disaccharide maltose; and lipase hydrolyzes triglycerides into fatty acids and glycerols. Pancreatin is an effective enzyme supplement for replacing missing pancreatic enzymes, and aids in the digestion of foods in cases of pancreatic insufficiency.
|
|
SLC45A4 is a member of the SLC45 family of solute carriers. Analysis of the protein function in a recombinant yeast expression assay show that it can: (i) transport a disaccharide,sucrose, as well simple sugars such as glucose and fructose (ii) perform secondary active transport in a proton-dependent manner. It is associated with sugar transport in the spermatozoa. Additionally, it has been itdentified as a necessary component in the cell death caused of the compound paraquat.
|
|
Both of these solutes are disaccharide heterosides which are extremely rare in thermophiles. Both are important in osmotic adaptation in microbes as well. With many questions to be answered about these two solutes, further research could benefit biotechnology in application to production of things such as food preservatives and textiles. Also, for scientists who are looking to further answer why and how hyperthermophiles survive, these two solutes could help fill in the missing pieces of the puzzle.
|
|
Lactose is a disaccharide found in animal milk. It consists of a molecule of D-galactose and a molecule of D-glucose bonded by beta-1-4 glycosidic linkage. A carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where m may be different from n). However, not all carbohydrates conform to this precise stoichiometric definition (e.g.
|
|
The infection stimulates the production of 5' hydroxytryptamine (serotonin). This activates vagal afferent nerves, which in turn activates the cells of the brain stem that control the vomiting reflex. Healthy enterocytes secrete lactase into the small intestine; milk intolerance due to lactase deficiency is a symptom of rotavirus infection, which can persist for weeks. A recurrence of mild diarrhoea often follows the reintroduction of milk into the child's diet, due to bacterial fermentation of the disaccharide lactose in the gut.
|
|
Galactose is a component of the antigens present on blood cells that determine blood type within the ABO blood group system. In O and A antigens, there are two monomers of galactose on the antigens, whereas in the B antigens there are three monomers of galactose. A disaccharide composed of two units of galactose, galactose-alpha-1,3-galactose (alpha-gal), has been recognized as a potential allergen present in mammal meat. Alpha-gal allergy may be triggered by lone star tick bites.
|
|
With his pupil Hans Horst Meyer he discovered glucuronic acid as a conjugation partner in xenobiotic metabolism and later found that glucuronic acid was also a component of cartilage and occurred as a disaccharide of chondroitin sulfate. He studied the composition of hyaluronic acid and explored its relationship to collagen, amyloid and chondroitin sulfate. In 1869 he demonstrated that muscarine had a similar effect on the heart as electrical stimulation of the vagus nerve. He also demonstrated the hypnotic properties of urethane.
|
|
Agar consists of a mixture of two polysaccharides: agarose and agaropectin, with agarose making up about 70% of the mixture. Agarose is a linear polymer, made up of repeating units of agarobiose, a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose. Agaropectin is a heterogeneous mixture of smaller molecules that occur in lesser amounts, and is made up of alternating units of D-galactose and L-galactose heavily modified with acidic side-groups, such as sulfate and pyruvate.Agar at lsbu.ac.
|
|
The specificity of the H antigen is determined by the sequence of oligosaccharides. More specifically, the minimum requirement for H antigenicity is the terminal disaccharide fucose-galactose, where the fucose has an alpha(1-2)linkage. This antigen is produced by a specific fucosyl transferase (Galactoside 2-alpha-L-fucosyltransferase 2) that catalyzes the final step in the synthesis of the molecule. Depending upon a person's ABO blood type, the H antigen is converted into either the A antigen, B antigen, or both.
|
|
Chondroitin sulfate nb R1, R2, R3 Hyaluronan (-4GlcUAβ1-3GlcNAcβ1-)n Glycosaminoglycans (GAGs) or mucopolysaccharides are long linear polysaccharides consisting of repeating disaccharide (double sugar) units. Except for keratan, the repeating unit consists of an amino sugar, along with a uronic sugar or galactose. Because GAGs are highly polar and attract water, they are used in the body as a lubricant or shock absorber. Mucopolysaccharidoses are a group of metabolic disorders in which abnormal accumulations of glycosaminoglycans occur because of enzyme deficiencies.
|
|
Naringenin has the skeleton structure of a flavanone with three hydroxy groups at the 4', 5, and 7 carbons. It may be found both in the aglycol form, naringenin, or in its glycosidic form, naringin, which has the addition of the disaccharide neohesperidose attached via a glycosidic linkage at carbon 7. Like the majority of flavanones, naringenin has a single chiral center at carbon 2, although the optical purity is variable. Racemization of S(-)-naringenin has been shown to occur fairly quickly.
|
|
SLC45A1 is a member of the SLC45 family of solute carriers. Analysis of the protein function in a recombinant yeast expression assay show that it can: (i) transport a disaccharide, such as glucose and sucrose (ii) perform secondary active transport in a proton-dependent manner. It is associated with sugar transport in the brain, and rare mutations in the gene are associated with intellectual disability and epilepsy. analgous to the effect of mutation of the cerebral glucose transporter GLUT1(SLC2A1).
|
|
Lager strains of S. cerevisiae secrete an enzyme called melibiase, allowing them to hydrolyse melibiose, a disaccharide, into more fermentable monosaccharides. Top- and bottom-cropping and cold- and warm-fermenting distinctions are largely generalizations used by laypersons to communicate to the general public.For more on the taxonomical differences, see The most common top- cropping brewer's yeast, S. cerevisiae, is the same species as the common baking yeast. Brewer's yeast is also very rich in essential minerals and the B vitamins (except B12).
|
|
This test is a diagnostic for GSID. Other tests which can aid in the diagnosis of GSID but which are not truly diagnostic for the disease are the sucrose breath test, and a genetic test which tests for the absence of certain genes which are thought to be responsible for GSID. Sucrose (also called saccharose) is a disaccharide and is a two-sugar chain composed of glucose and fructose which are bonded together. A more familiar name is table, beet, or cane sugar.
|
|
People who maintain a healthy, Japanese, or Mediterranean diet have a reduced risk of AD. A Mediterranean diet may improve outcomes in those with the disease. Those who eat a diet high in saturated fats and simple carbohydrates (mono- and disaccharide) have a higher risk. The Mediterranean diet's beneficial cardiovascular effect has been proposed as the mechanism of action. Conclusions on dietary components have at times been difficult to ascertain as results have differed between population-based studies and randomised controlled trials.
|
|
In 1980, it was discovered that B. pertussis could attach to hamster tracheal epithelial (HTE) cells, and also, that the supernatant from the cultured bacterium could disrupt the cell cycle of uninfected cells. This prompted the scientists W. E. Goldman, D. G. Klapper, and J. B. Baseman to isolate and characterize a novel substance from B. pertussis supernatant. The novel disaccharide tetrapeptide that they had purified showed toxicity for HTE cells and tracheal ring cultures. Subsequently, they named the newly sequestered molecule tracheal cytotoxin (TCT).
|
|
Lactase can be purchased as a food supplement, and is added to milk to produce "lactose- free" milk products. Lactase (also known as lactase-phlorizin hydrolase, or LPH), a part of the β-galactosidase family of enzymes, is a glycoside hydrolase involved in the hydrolysis of the disaccharide lactose into constituent galactose and glucose monomers. Lactase is present predominantly along the brush border membrane of the differentiated enterocytes lining the villi of the small intestine. In humans, lactase is encoded by the LCT gene.
|
|
There are three major structural domains for arabinan. The first is a domain consisting of linear 5-linked α-D- Araf residues. The second is a domain with branched 3,5 linked α-D-Araf residues substituted with 5-linked α-D-Araf units at both branched positions, and the third is A terminal non-reducing domain for end arabinan consisting of a 3,5-linked α-D-Araf residue substituted at both branched positions with the disaccharide β-D Araf-(1→2)- α-D-Araf.
|
|
Chitin disaccharide deacetylase (, chitobiose amidohydolase, COD, chitin oligosaccharide deacetylase, chitin oligosaccharide amidohydolase) is an enzyme with systematic name 2-(acetylamino)-4-O-(2-(acetylamino)-2-deoxy-beta- D-glucopyranosyl)-2-deoxy-D-glucopyranose acetylhydrolase. This enzyme catalyses the following chemical reaction : 2-(acetylamino)-4-O-[2-(acetylamino)-2-deoxy-beta-D-glucopyranosyl]-2-deoxy- beta-D-glucopyranose + H2O \rightleftharpoons 2-(acetylamino)-4-O-(2-amino-2-deoxy-beta-D-glucopyranosyl)-2-deoxy-beta-D- glucopyranose + acetate Chitin oligosaccharide deacetylase is present in Vibrio strains.
|
|
Chitobiose is the condensed form of 4‐O‐(2‐amino‐2‐deoxy‐β‐d‐glucopyranosyl)‐2‐amino‐2‐deoxy‐d‐glucose and is an acetylation disaccharide found in chitin. Chitobiose is utilized by B. burgdorferi to produced N-Acetylglucosamine, a component of the bacterial cell wall, and is regularized by the response regulator rrp1. A mutant strain of rrp1 has been found to cause growth deficits with B. burgdorferi. In Escherichia coli, the chb operon is involved with the utilization of cellobiose and β-glucosides chitobiose.
|
|
Brettanomyces is most associated with barrel aged red wines, but has also been found in Chardonnay and Sauvignon blanc. In some cases the yeast has caused contamination in sparkling wines produced by the Méthode champenoise when en tirage. It is thought Brettanomyces can be introduced to a winery by insect vectors such as fruit flies, or by purchasing Brett contaminated wine barrels. The ability to metabolise the disaccharide cellobiose, along with the irregular surface of a barrel interior, provide ideal conditions for Brettanomyces growth.
|
|
Lipid A is, in normal circumstances, a phosphorylated glucosamine disaccharide decorated with multiple fatty acids. These hydrophobic fatty acid chains anchor the LPS into the bacterial membrane, and the rest of the LPS projects from the cell surface. The lipid A domain is responsible for much of the toxicity of Gram-negative bacteria. When bacterial cells are lysed by the immune system, fragments of membrane containing lipid A are released into the circulation, causing fever, diarrhea, and possible fatal endotoxic shock (also called septic shock).
|
|
Lactose is a disaccharide sugar composed of galactose and glucose that is found in milk. Lactose can not be absorbed by the intestine and needs to be split in the small intestine into galactose and glucose by the enzyme called lactase; unabsorbed lactose can cause abdominal pain, bloating, diarrhea, gas, and nausea. In most mammals, production of lactase diminishes after infants are weaned from maternal milk. However, 5% to 90% of the human population possess an advantageous autosomal mutation in which lactase production persists after infancy.
|
|
Hydrolysis of the disaccharide lactose to glucose and galactose Milk allergy is distinct from lactose intolerance, which is a nonallergic food sensitivity, due to the lack of the enzyme lactase in the small intestines to break lactose down into glucose and galactose. The unabsorbed lactose reaches the large intestine, where resident bacteria use it for fuel, releasing hydrogen, carbon dioxide and methane gases. These gases are the cause of abdominal pain and other symptoms. Lactose intolerance does not cause damage to the gastrointestinal tract.
|
|
Unsaturated chondroitin disaccharide hydrolase (, UGL, unsaturated glucuronyl hydrolase) is an enzyme with systematic name beta-D-4-deoxy- Delta4-GlcAp-(1->3)-beta-D-GalNAc6S hydrolase. This enzyme catalyses the following chemical reaction : beta-D-4-deoxy-Delta4-GlcAp-(1->3)-beta-D- GalNAc6S + H2O \rightleftharpoons 5-dehydro-4-deoxy-D-glucuronate + N-acetyl- beta-D-galactosamine-6-O-sulfate The enzyme releases 4-deoxy-4,5-didehydro D-glucuronic acid or 4-deoxy-4,5-didehydro L-iduronic acid from chondroitin disaccharides, hyaluronan disaccharides and heparin disaccharides.
|
|
Sucrose is a disaccharide made up of 50% glucose and 50% fructose and has a glycemic index of 65. Sucrose is digested rapidly, but has a relatively low glycemic index due to its content of fructose, which has a minimal effect on blood glucose. As with other sugars, sucrose is digested into its components via the enzyme sucrase to glucose (blood sugar). The glucose component is transported into the blood where it serves immediate metabolic demands, or is converted and reserved in the liver as glycogen.
|
|
Honey bees ingest phytosterols from pollen to produce 24-methylenecholesterol and other sterols as they cannot directly synthesize cholesterol from phytosterols. Nurse bees have the ability to selectively transfer sterols to larvae through brood food. Nectar is collected by foraging worker bees as a source of water and carbohydrates in the form of sucrose. The dominant monosaccharides in honey bee diets are fructose and glucose but the most common circulating sugar in hemolymph is trehalose which is a disaccharide consisting of two glucose molecules.
|
|
From PLOD2 two splice variant can be expressed (LH2a and LH2b), where LH2b differs from LH2a by incorporating the small exon 13A. LH1 and LH3 hydroxylate lysyl residues in the collagen triple helix, whereas LH2b hydroxylates lysyl residues in the telopeptides of collagen. In addition to its hydroxylation activity, LH3 has glycosylation activity that produces either monosaccharide (Gal) or disaccharide (Glc-Gal) attached to collagen hydroxylysines. Collagen lysyl hydroxylation is the first step in collagen pyridinoline cross-linking, that is necessary for the stabilization of collagen.
|
|
Maltose Maltase (, alpha-glucosidase, glucoinvertase, glucosidosucrase, maltase-glucoamylase, alpha-glucopyranosidase, glucosidoinvertase, alpha-D- glucosidase, alpha-glucoside hydrolase, alpha-1,4-glucosidase, alpha-D- glucoside glucohydrolase) is an enzyme located in on the brush border of the small intestine that breaks down the disaccharide maltose. Maltase catalyzes the hydrolysis of maltose to the simple sugar glucose. This enzyme is found in plants, bacteria, and yeast. Acid maltase deficiency is categorized into three separate types based on the age of onset of symptoms in the affected individual.
|
|
MurJ has 14 TMSs, and specific charged residues localized in the central cavity are essential for function. This structural homology model suggests that MurJ functions as an essential transporter in PG biosynthesis. Based on an in vivo assay, MurJ acts as a flippase for the lipid-linked cell wall precursor, polyisoprenoid-linked disaccharide- peptapeptide. There is controversy about the role of this porter and FtsW/RodA which on the basis of an in vitro assay, were thought to be flippases for the same intermediate.
|
|
Chloroeremomycin is composed of seven amino acids (three non-proteinogenic, and four proteinogenic) and three saccharide units. From N-terminus to C-terminus, the order is: Me-L-Leu, L-Tyr, D-Asn, D-4-hydroxyphenylglycine (HPG), L-HPG, D-Tyr, and D-3,5-dihydroxyphenylglycine (DHPG). When referring to specific amino acids, this article will reference the amino acid in the order it appears within the heptapeptide. Chloroeremomycin is glycosylated at aa4 with a Glc-(2→α1)-epivancosamine disaccharide and at aa6 with a D-BHT-(→α1)-epivancosamine saccharide.
|
|
Melibiose is a reducing disaccharide formed by an α-1,6 linkage between galactose and glucose (D-Gal-α(1→6)-D-Glc). It differs from lactose in the chirality of the carbon where the galactose ring is closed and that the galactose is linked to a different point on the glucose moiety. It can be formed by invertase-mediated hydrolysis of raffinose, which produces melibiose and fructose. Melibiose can be broken down into its component saccharides, glucose and galactose, by the enzyme alpha-galactosidase, such as MEL1 from Saccharomyces pastorianus (lager yeast).
|
|
In enzymology, a chondroitin B lyase () is an enzyme that catalyzes the chemical reaction :Eliminative cleavage of dermatan sulfate containing 1,4-beta-D-hexosaminyl and 1,3-beta-D-glucurosonyl or 1,3-alpha-L-iduronosyl linkages to disaccharides containing 4-deoxy-beta-D-gluc-4-enuronosyl groups to yield a 4,5-unsaturated dermatan-sulfate disaccharide (deltaUA-GalNAc-4S). This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. The systematic name of this enzyme class is chondroitin B lyase. Other names in common use include chondroitinase B, ChonB, and ChnB.
|
|
Glyceraldehyde-3-phosphate can double up to form larger sugar molecules like glucose and fructose. These molecules are processed, and from them, the still larger sucrose, a disaccharide commonly known as table sugar, is made, though this process takes place outside of the chloroplast, in the cytoplasm. Alternatively, glucose monomers in the chloroplast can be linked together to make starch, which accumulates into the starch grains found in the chloroplast. Under conditions such as high atmospheric CO2 concentrations, these starch grains may grow very large, distorting the grana and thylakoids.
|
|
Washing of the fermented beans leads to wastewater containing mainly pectins from the mucilage, proteins and sugars. The fermentation of the sugars (disaccharide carbohydrates) into ethanol and CO2 leads to acid conditions in the washing water. The ethanol is converted in acetic acids after reaction with oxygen, lowering the pH to levels of around 4. The high acidity can negatively affect the treatment efficiency of treatment facilities treating the coffee wastewater like an anaerobic reactor or constructed wetlands and is considered to be detrimental for aquatic life when discharged directly into surface waters.
|
|
During winter, their haemolymph contains low molecular weight cryoprotectants such as amino acids, especially proline (up to about 100 mM) and the disaccharide trehalose. These substances are synthesised during autumn and their concentration decreases again during spring and summer (proline concentration decreases to about 10 mM during summer). The amino acids and sugars presumably help to decrease the ice content colligatively; however, they probably also have a direct protective effect on membranes and proteins via direct interaction or by modifying the water layer with the closest proximity to the molecules.
|
|
The absorption capacity for fructose in monosaccharide form ranges from less than 5 g to 50 g (per individual serving) and adapts with changes in dietary fructose intake. Studies show the greatest absorption rate occurs when glucose and fructose are administered in equal quantities. When fructose is ingested as part of the disaccharide sucrose, absorption capacity is much higher because fructose exists in a 1:1 ratio with glucose. It appears that the GLUT5 transfer rate may be saturated at low levels, and absorption is increased through joint absorption with glucose.
|
|
MOGS is highly specific to the oligosaccharide in its biological substrate in the N-glycosylation pathway. Eukaryotic MOGS does not cleave simple substrates such as p-nitrophenyl glucose, and it also shows no activity to the α(1→3) linkage present at the terminus of Glc1-2Man9GlcNAc2. Furthermore, the minimum substrate is the glucotriose molecule (Glc-α(1→2)-Glc-α(1→3)-Glc), linked as in its native Glc3Man9GlcNAc2 substrate. Kojibiose, the disaccharide Glc-α(1→2)-Glc, acts as a weak inhibitor on plant, animal, and yeast MOGS.
|
|
The toxic rotavirus protein NSP4 induces age- and calcium ion- dependent chloride secretion, disrupts SGLT1 transporter-mediated reabsorption of water, apparently reduces activity of brush-border membrane disaccharidases, and possibly activates the calcium ion-dependent secretory reflexes of the enteric nervous system. Healthy enterocytes secrete lactase into the small intestine; milk intolerance due to lactase deficiency is a symptom of rotavirus infection, which can persist for weeks. A recurrence of mild diarrhoea often follows the reintroduction of milk into the child's diet, due to bacterial fermentation of the disaccharide lactose in the gut.
|
|
For example, the aldohexose glucose may form a hemiacetal linkage between the hydroxyl on carbon 1 and the oxygen on carbon 4, yielding a molecule with a 5-membered ring, called glucofuranose. The same reaction can take place between carbons 1 and 5 to form a molecule with a 6-membered ring, called glucopyranose. Cyclic forms with a 7-atom ring called heptoses are rare. Two monosaccharides can be joined together by a glycosidic or ether bond into a disaccharide through a dehydration reaction during which a molecule of water is released.
|
|
Pectins, also known as pectic polysaccharides, are rich in galacturonic acid. Several distinct polysaccharides have been identified and characterised within the pectic group. Homogalacturonans are linear chains of α-(1–4)-linked D-galacturonic acid. Substituted galacturonans are characterized by the presence of saccharide appendant residues (such as D-xylose or D-apiose in the respective cases of xylogalacturonan and apiogalacturonan) branching from a backbone of D-galacturonic acid residues. Rhamnogalacturonan I pectins (RG-I) contain a backbone of the repeating disaccharide: 4)-α-D-galacturonic acid-(1,2)-α-L- rhamnose-(1.
|
|
Amylase reaction consisting of hydrolyzing amylose, producing maltose Maltose (Dictionary Reference: maltose or Cambridge dictionary: maltose), also known as maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) bond. In the isomer isomaltose, the two glucose molecules are joined with an α(1→6) bond. Maltose is the two-unit member of the amylose homologous series, the key structural motif of starch. When beta- amylase breaks down starch, it removes two glucose units at a time, producing maltose.
|
|
Isomaltooligosaccharide (IMO), more commonly known as isomalto- oligosaccharide, is a mixture of short-chain carbohydrates which may have a digestion-resistant property. IMO is found naturally in some foods, as well as being manufactured commercially. Although isomaltose is found in some foods, such as honey, as a disaccharide, it behaves like all other disaccharides and is easily digested. Because of a confusion over nomenclature, such disaccharides have frequently been described as IMO, however to truly be called an "oligosaccharide" the molecules must have a degree of polymerization (DP) of three or more.
|
|
A cord factor molecule is composed of a trehalose sugar, a disaccharide, that is esterified to two mycolic acid residues. One of the two mycolic acid residues is attached to the sixth carbon of one monosaccharide, while the other mycolic acid residue is attached to the sixth carbon of the other monosaccharide. Therefore, cord factor is also named trehalose-6,6'-dimycolate. The carbon chain of the mycolic acid residues vary in length depending on the species of bacteria it is found in, but the general range is 20 to 80 carbon atoms.
|
|
In enzymology, a chondroitin-sulfate-ABC exolyase () is an enzyme that catalyzes the chemical reaction :Exolytic cleavage of disaccharide residues from the non-reducing ends of both polymeric chondroitin sulfates and their oligosaccharide fragments This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. The systematic name of this enzyme class is chondroitin-sulfate-ABC exolyase. Other names in common use include chondroitinase (ambiguous), chondroitin ABC eliminase (ambiguous), chondroitinase ABC (ambiguous), chondroitin ABC lyase (ambiguous), chondroitin sulfate ABC lyase (ambiguous), ChS ABC lyase (ambiguous), chondroitin sulfate ABC exoeliminase, chondroitin sulfate ABC exolyase, and ChS ABC lyase II.
|
|
As well as assisting in adherence to epithelial cells, some of these are also involved in attachment to immune effector cells. The initial catarrhal phase of infection produces symptoms similar to those of the common cold, and during this period, large numbers of bacteria can be recovered from the pharynx. Thereafter, the bacteria proliferate and spread further into the respiratory tract, where the secretion of toxins causes ciliostasis and facilitates the entry of bacteria to tracheal/bronchial ciliated cells. One of the first toxins to be expressed is tracheal cytotoxin, which is a disaccharide-tetrapeptide derived from peptidoglycan.
|
|
The active site of β-galactosidase catalyzes the hydrolysis of its disaccharide substrate via "shallow" (nonproductive site) and "deep" (productive site) binding. Galactosides such as PETG and IPTG will bind in the shallow site when the enzyme is in "open" conformation while transition state analogs such as L-ribose and D-galactonolactone will bind in the deep site when the conformation is "closed". The enzymatic reaction consists of two chemical steps, galactosylation (k2) and degalactosylation (k3). Galactosylation is the first chemical step in the reaction where Glu461 donates a proton to a glycosidic oxygen, resulting in galactose covalently bonding with Glu537.
|
|
Carbohydrates include the common sugar, sucrose (table sugar), a disaccharide, and such simple sugars as glucose (made by enzymatic splitting of sucrose) and fructose (from fruit), and starches from sources such as cereal flour, rice, arrowroot and potato. The interaction of heat and carbohydrate is complex. Long-chain sugars such as starch tend to break down into simpler sugars when cooked, while simple sugars can form syrups. If sugars are heated so that all water of crystallisation is driven off, then caramelization starts, with the sugar undergoing thermal decomposition with the formation of carbon, and other breakdown products producing caramel.
|
|
V1 isoforms has the GAG-β domain, V2 has the GAG-α domain, V3 is void of any GAG attachment domains and V4 has a portion of the GAG-β domain. The GAGs, being composed of repeating disaccharide units, contribute to the negative charge and many other properties of proteoglycans. The C-terminal (G3) globular domain consists of one or two Epidermal growth factor (EGF) repeats, a C-type lectin domain and complement regulatory protein (CRP)-like domain. The C-terminal domain binds a variety of ligands in ECM which contribute significantly to the functions of lecticans.
|
|
Fructose, or fruit sugar, is a simple ketonic monosaccharide found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into blood during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847.Dubrunfaut (1847) "Sur une propriété analytique des fermentations alcoolique et lactique, et sur leur application à l’étude des sucres" (On an analytic property of alcoholic and lactic fermentations, and on their application to the study of sugars), Annales de Chimie et de Physique, 21 : 169–178.
|
|
Figure 4: Hydrolysis of sucrose to glucose and fructose by sucrase Figure 5: Intestinal sugar transport proteins Fructose exists in foods either as a monosaccharide (free fructose) or as a unit of a disaccharide (sucrose). Free fructose is absorbed directly by the intestine. When fructose is consumed in the form of sucrose, it is digested (broken down) and then absorbed as free fructose. As sucrose comes into contact with the membrane of the small intestine, the enzyme sucrase catalyzes the cleavage of sucrose to yield one glucose unit and one fructose unit, which are then each absorbed.
|
|
Crocetin is a 20-carbon chain dicarboxylic acid which is a diterpenenoid and can be considered as a carotenoid. It was the first plant carotenoid to be recognized as early as 1818 while the history of saffron cultivation reaches back more than 3,000 years. The major active ingredient of saffron is the yellow pigment crocin 2 (three other derivatives with different glycosylations are known) containing a gentiobiose (disaccharide) group at each end of the molecule. A simple and specific HPLC-UV method has been developed to quantify the five major biologically active ingredients of saffron, namely the four crocins and crocetin.
|
|
Galactosidases are enzymes (glycoside hydrolases) that catalyze the hydrolysis of galactosides into monosaccharides. Galactosides can be classified as either alpha or beta. If the galactoside is classified as an alpha-galactoside, the enzyme is called alpha-galactosidase, and is responsible for catalyzing the hydrolysis of substrates that contain α-galactosidic residues, such as glycosphingolipids or glycoproteins. On the other hand, if it is a beta- galactoside, it is called beta-galactosidase, and is responsible for breaking down the disaccharide lactose into its monosaccharide components, glucose and galactose Both varieties of galactosidase are categorized under the EC number 3.2.1.
|
|
The cell wall of both gram-positive and gram-negative bacteria is a tight covalently bound and cross-linked peptidoglycan network and essential for bacterial growth, cell division and cellular structure. Therefore, bacteria need enzymes that can cleave the cell wall during bacterial growth and cell division. The cell wall of bacteria is built up in two steps from the outside of the cell. In the first step, molecules of disaccharide units linked with peptides on their ends are transported from the cytoplasm of the bacteria and joined together on the outside of the wall by a transglycolase.
|
|
Humans and higher primates also produce "natural antibodies" that are present in serum before viral infection. Natural antibodies have been defined as antibodies that are produced without any previous infection, vaccination, other foreign antigen exposure or passive immunization. These antibodies can activate the classical complement pathway leading to lysis of enveloped virus particles long before the adaptive immune response is activated. Many natural antibodies are directed against the disaccharide galactose α(1,3)-galactose (α-Gal), which is found as a terminal sugar on glycosylated cell surface proteins, and generated in response to production of this sugar by bacteria contained in the human gut.
|
|
This end product acts as a carrier of N-Acetylglucosamine, which is the monomeric unit of chitin, a structural polymer that composes the shells of crustaceans and insects, as well as the cell wall of fungi. Furthermore, N-Acetylglucosamine is also a unit of the peptidoglycan polymer that composes the bacteria cell wall along with N-acetylmuramic disaccharide. Figure 1: As shown in the picture, there are two possible pathways to produce UDP-N-Acetyl-D-Glucosamide from D-Fructose-6-phosphate. In eukaryotes, GNA is present and the acetylation occurs before the phosphate transfer from the 6-carbon to the 1-carbon.
|
|
The fourth class of GAG, hyaluronic acid, is not sulfated and is synthesized by three transmembrane synthase proteins HAS1, HAS2, and HAS3. HA, a linear polysaccharide, is composed of repeating disaccharide units of →4)GlcAβ(1→3)GlcNAcβ(1→ and has a very high molecular mass, ranging from 105 to 107 Da. Each HAS enzyme is capable of transglycosylation when supplied with UDP-GlcA and UDP-GlcNAc. HAS2 is responsible for very large hyaluronic acid polymers, while smaller sizes of HA are synthesized by HAS1 and HAS3. While each HAS isoform catalyzes the same biosynthetic reaction, each HAS isoform is independently active.
|
|
It is a disaccharide formed from one molecule each of the simple sugars (monosaccharides) fructose and galactose. Lactulose is not normally present in raw milk, but is a product of heat processes: the greater the heat, the greater amount of this substance (from 3.5 mg/l in low-temperature pasteurized milk to 744 mg/l in in-container sterilized milk). It is produced commercially by isomerization of lactose. Lactulose is not absorbed in the small intestine nor broken down by human enzymes, thus stays in the digestive bolus through most of its course, causing retention of water through osmosis leading to softer, easier-to-pass stool.
|
|
In enzymology, a levan fructotransferase (DFA-IV-forming) () is an enzyme that catalyzes the chemical reaction :Produces di-beta-D-fructofuranose 2,6':2',6-dianhydride (DFA IV) by successively eliminating the diminishing (2->6)-beta-D-fructan (levan) chain from the terminal D-fructosyl-D-fructosyl disaccharide This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. The systematic name of this enzyme class is 2,6-beta-D-fructan lyase (di-beta-D- fructofuranose-2,6':2',6-dianhydride-forming). Other names in common use include 2,6-beta-D-fructan D-fructosyl-D-fructosyltransferase (forming, di- beta-D-fructofuranose 2,6':2',6-dianhydride), and levan fructotransferase.
|
|
Essentially, these experiments display that a fine-tuned 6-O sulfation pattern is needed for proper function of VSMCs. Sulf2 was investigated with respect to angiogenesis in a chick model. In contrast to Sulf1, Sulf2 actually induced angiogenesis in a chick chorioallantoic membrane assay. Sulf2 was measured for its ability to modulate binding of growth factors to trisulfated disaccharide motif heparin and HS. Sulf2 inhibited both pre- and post-binding of VEGF165, FGF-1, and SDF-1, a HS-binding chemokine, to both heparin and HS. Investigators hypothesize that Sulf-2 may mobilize ECM- sequestered angiogenic factors, increasing their bioavailability to endothelial cells that express the appropriate receptors.
|
|
Polysulfated glycosaminoglycan (PSGAG), sold under the brand name Adequan, is an injectable drug for dogs and horses that is used to alleviate the lameness, pain, and lowered range of motion caused by arthritis. It is made of repeat disaccharide units (comprising hexosamine and hexuronic acid), and is similar to glycosaminoglycans already present in the cartilage; PSAG thus easily integrates itself there. In vitro studies have shown it to inhibit the enzymes that degrade cartilage and bone, as well as suppress inflammation and stimulate the synthesis of replacement cartilage. While it can cause an increased risk of bleeding, its relatively safe and has a high LD50.
|
|
The most common structure of Wall teichoic acids are a ManNAc(β1→4)GlcNAc disaccharide with one to three glycerol phosphates attached to the C4 hydroxyl of the ManNAc residue followed by a long chain of glycerol- or ribitol phosphate repeats. Variations come in the long chain tail, which generally include sugar subunits being attached to thee sides or the body of the repeats. Four types of WTA repeats have been named, as of 2013. Lipoteichoic acids follow a similar pattern of putting most variation in the repeats, although the set of enzymes used are different, at least in the case of Type I LTA.
|
|
RebO (a tryptophan oxidase) then deaminates, after which it is further reacted with another one of itself and RebD (a heme containing oxidase). This forms the majority of the carbon backbone, which then undergoes decarboxylative ring closure using RebC and RebP. A glycosylation occurs using RebG and NDP-D- glucose, which finally goes through methylation by RebM. These latter tailoring enzymes have been noted as permissive in terms of both aglycons/acceptors and glycosyl/alkyl donors. A parallel pathway has been put forth for the structurally related disaccharide-substituted indolocarbazole AT2433, the aminopentose of which is also found appended to the 10-membered enediyne calicheamicin.
|
|
Lactose intolerance is a consequence of lactase deficiency, which may be genetic (primary hypolactasia and primary congenital alactasia) or environmentally induced (secondary or acquired hypoalactasia). In either case, symptoms are caused by insufficient levels of lactase in the lining of the duodenum. Lactose, a disaccharide molecule found in milk and dairy products, cannot be directly absorbed through the wall of the small intestine into the bloodstream, so, in the absence of lactase, passes intact into the colon. Bacteria in the colon can metabolise lactose, and the resulting fermentation produces copious amounts of gas (a mixture of hydrogen, carbon dioxide, and methane) that causes the various abdominal symptoms.
|
|
A handful of malted barley, the white sprouts visible Beer malt varieties from Bamberg, Germany Malt is germinated cereal grain that has been dried in a process known as "malting". The grain is made to germinate by soaking in water and is then halted from germinating further by drying with hot air. Malting grain develops the enzymes (α-amylase, β-amylase) required for modifying the grains' starches into various types of sugar, including monosaccharide glucose, disaccharide maltose, trisaccharide maltotriose, and higher sugars called maltodextrines. It also develops other enzymes, such as proteases, that break down the proteins in the grain into forms that can be used by yeast.
|
|
Glycoside hydrolase family 7 CAZY GH_7 comprises enzymes with several known activities including endoglucanase () and cellobiohydrolase (). These enzymes were formerly known as cellulase family C. Exoglucanases and cellobiohydrolases play a role in the conversion of cellulose to glucose by cutting the disaccharide cellobiose from the non-reducing end of the cellulose polymer chain. Structurally, cellulases and xylanases frequently consist of a catalytic domain joined to a cellulose-binding domain (CBD) via a linker region that is rich in proline and/or hydroxy-amino acids. In type I exoglucanases, the CBD domain is found at the C-terminal extremity of these enzyme (this short domain forms a hairpin loop structure stabilised by 2 disulphide bridges).
|
|
Sucrose is a disaccharide formed from condensation of glucose and fructose to produce α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside. Sucrose has 8 hydroxyl groups which can be reacted with fatty acid esters to produce sucrose esters. Among the 8 hydroxyl groups on sucrose, three (C6, C1', and C6') are primary while the others (C2, C3, C4, C3', and C4') are secondary. (The numbers 1-6 indicate the position of the carbons on glucose while the numbers 1'-6' indicate the position of the carbons on fructose.) The three primary hydroxyl groups are more reactive due to lower steric hindrance, so they react with fatty acids first, resulting in a sucrose mono-, di-, or triester.
|
|
The major challenge in the analysis of heparin impurities is the detection and identification of structurally related impurities. The most prevalent impurity in heparin is dermatan sulfate (DS), also known as chondroitin sulfate B. The building-block of DS is a disaccharide composed of 1,3-linked N-acetyl galactosamine (GalN) and a uronic acid residue, connected via 1,4 linkages to form the polymer. DS is composed of three possible uronic acid (GlcA, IdoA or IdoA2S) and four possible hexosamine (GalNAc, Gal- NAc4S, GalNAc6S, or GalNAc4S6S) building-blocks. The presence of iduronic acid in DS distinguishes it from chrondroitin sulfate A and C and likens it to heparin and HS. DS has a lower negative charge density overall compared to heparin.
|
|
In enzymology, an inulin fructotransferase (DFA-I-forming) () is an enzyme that catalyzes the chemical reaction :Produces alpha-D-fructofuranose beta-D- fructofuranose 1,2':2,1'-dianhydride (DFA I) by successively eliminating the diminishing (2->1)-beta-D-fructan (inulin) chain from the terminal D-fructosyl-D-fructosyl disaccharide. This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. The systematic name of this enzyme class is 2,1-beta-D-fructan lyase (alpha-D- fructofuranose-beta-D-fructofuranose-1,2':2,1'-dianhydride- forming). Other names in common use include inulin fructotransferase (DFA-I-producing), inulin fructotransferase (depolymerizing,, difructofuranose-1,2':2',1-dianhydride- forming), inulin D-fructosyl-D-fructosyltransferase, (1,2':1',2-dianhydride- forming), inulin D-fructosyl-D-fructosyltransferase (forming, and alpha-D- fructofuranose beta-D-fructofuranose 1,2':1',2-dianhydride).
|
|
Braunwald E; Fauci AS; Kasper DL; Hauser SL; Longo DL; Jameson JL, eds. Harrison's Principles of Internal Medicine, 15th ed. McGraw-Hill Companies, 2001 ;Preface xxxi. Over the subsequent 30 years, his division became one of the leading centers of training, research and treatment of gastrointestinal diseases in the United States. His research during this period included the description and elucidation of a new hereditary disorder of leucine metabolism called isovaleric acidemia, the definition of enzymatic defects in absorptive disorders, delineations of biochemical mechanism of nutrient absorption,PlotkinGR; Isselbacher KJ (Nov 12, 1964) Secondary Disaccharide Deficiency in Adult Celiac Disease New England Journal of Medicine 271 1033-1037 malabsorption,Isselbacher KJ (Jan- Feb 1965) Metabolism and Transport of Lipid by Intestinal Mucosa Federation Proceedings 24 16-22 and protein synthesis, derangements of metabolism and immunologic aspects of hepatic gastrointestinal diseases.
|
|
In enzymology, a lipid-A-disaccharide synthase () is an enzyme that catalyzes the chemical reaction :UDP-2,3-bis(3-hydroxytetradecanoyl)glucosamine + 2,3-bis(3-hydroxytetradecanoyl)-beta-D-glucosaminyl 1-phosphate \rightleftharpoons UDP + 2,3-bis(3-hydroxytetradecanoyl)-D-glucosaminyl-1,6-beta-D-2,3-bis(3-hydroxytetradecanoyl)-beta- D-glucosaminyl 1-phosphate Thus, the two substrates of this enzyme are UDP-2,3-bis(3-hydroxytetradecanoyl)glucosamine and 2,3-bis(3-hydroxytetradecanoyl)-beta-D-glucosaminyl 1-phosphate, whereas its 2 products are UDP and 2,3-bis(3-hydroxytetradecanoyl)-D-glucosaminyl-1,6-beta-D-2,3-bis(3-hydroxytetradecanoyl)-beta- D-glucosaminyl 1-phosphate. This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-2,3-bis(3-hydroxytetradecanoyl)glucosamine:2,3-bis-(3-hydroxytet radecanoyl)-beta-D-glucosaminyl-1-phosphate 2,3-bis(3-hydroxytetradecanoyl)-glucosaminyltransferase. This enzyme participates in lipopolysaccharide biosynthesis.
|
|
" In 1998, Horvath published a paper describing Parker, Aaron and one other child (who also had autism) in the Journal of the Association for Academic Minority Physicians. The paper stated that these three children had undergone upper gastrointestinal endoscopy with intravenous secretin administration, and that, subsequently, the children's gastrointestinal and behavioral symptoms had both improved significantly. As a result of this research, the University of Maryland (where Horvath was working at the time) filed a patent application for the use of secretin to treat autism, but ended up giving the rights to the patent to Beck, since she was the first to suspect that secretin might be an effective autism treatment. In 1999, Horvath published another study of 36 children, which concluded that "Unrecognized gastrointestinal disorders, especially reflux esophagitis and disaccharide malabsorption, may contribute to the behavioral problems of the non-verbal autistic patients." In an accompanying editorial, Pasquale Accardo and Howard Bostwick of New York Medical College wrote that Horvath's study "demonstrates consistent physiologic abnormalities (increased density of Paneth’s cells along with diminished pancreatic secretin secretion) in autism that are not known to occur in any other specific gastrointestinal disorder.
|
|