Disaccharides

Sucrose is a disaccharide, a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula .

Lactose is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from (gen. ), the Latin word for milk, plus the suffix -ose used to name sugars. The compound is a white, water-soluble, non-hygroscopic solid with a mildly sweet taste. It is used in the food industry.

thumb|right|260px|Amylase reaction consisting of hydrolyzing amylose, producing maltose

thumb|287x287px|Sucrose, a disaccharide formed from condensation of a molecule of glucose and a molecule of fructose A disaccharide (also called a double sugar or biose) is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars soluble in water. Three common examples are sucrose, lactose, and maltose.

Lactulose is a non-absorbable sugar used in the treatment of constipation and hepatic encephalopathy. It is administered orally for constipation, and either orally or rectally for hepatic encephalopathy. It generally begins working after 8–12 hours, but may take up to 2 days to improve constipation.

thumb|Sucralose: (C12H19Cl3O8) Black Carbon, White Hydrogen, Green Chlorine, Red Oxygen Sucralose is an artificial sweetener and sugar substitute. In the European Union, it is also known under the E number E955. It is produced by chlorination of sucrose, selectively replacing three of the hydroxy groups—in the C1 and C6 positions of the fructose portion and the C4 position of the glucose portion—to give a 1,6-dichloro-1,6-dideoxyfructose–4-chloro-4-deoxygalactose disaccharide. Sucralose is about 600 times sweeter than sucrose (table sugar), 3 times as sweet as both aspartame a

thumb|Crystalline trehalose dihydrate powder Trehalose is a sugar derived from two molecules of glucose. Trehalose is a disaccharide formed by a bond between two α-glucose units. It is found in nature as a disaccharide and also as a monomer in some polymers. Two other stereoisomers exist: α,β-trehalose, also called neotrehalose, and β,β-trehalose, also called isotrehalose. Neither of these alternate isomers has been isolated from living organisms, but isotrehalose has been found in starch hydroisolates. Some bacteria, fungi, plants and invertebrate animals synthesize trehalose as a source of e

Lactitol is a disaccharide sugar alcohol produced from lactose. It is used as a replacement bulk sweetener for low calorie foods with 30–40% of the sweetness of sucrose. It is also used medically as a laxative.

Cellobiose is a disaccharide with the formula (C6H7(OH)4O)2O. It is classified as a reducing sugar - any sugar that possesses the ability or function of a reducing agent. The chemical structure of cellobiose is derived from the condensation of a pair of glucose molecules forming a β(1→4) bond. It can be hydrolyzed to glucose enzymatically or with acid. Cellobiose has eight free alcohol (OH) groups, one acetal linkage, and one hemiacetal linkage, which give rise to strong inter- and intramolecular hydrogen bonds. It is a white solid.

Isomalt is a sugar substitute, a mixture of the two disaccharide alcohols 1,6-GPS and 1,1-GPM. It is used primarily for its sugar-like physical properties. It has little to no impact on blood sugar levels, and does not stimulate the release of insulin. It also does not promote tooth decay and is considered to be tooth-friendly. Its energy value is 2 kcal per gram, half that of sugars. It is less sweet than sugar, but can be blended with high-intensity sweeteners such as sucralose to create a mixture with the same sweetness as sucrose (‘sugar’).

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. During a starch hydrolysis process for glucose syrup, gentiobiose, which has bitterness, is formed as an undesirable product through the acid-catalyzed condensation reaction of two D-glucose molecules. A further elongation of the unit elongation of the bitter di

Isomaltulose (trade name Palatinose, chemical name '6-O-α-D-glucopyranosyl-D-fructose') is a disaccharide carbohydrate composed of glucose and fructose. It is naturally present in honey and sugarcane extracts and is also produced industrially from table sugar (sucrose) and used as a sugar alternative.

Sucralfate, sold under various brand names, is a medication used to treat stomach ulcers, gastroesophageal reflux disease (GERD), radiation proctitis, and stomach inflammation and to prevent stress ulcers. Its usefulness in people infected by H. pylori is limited. It is used by mouth (for ulcers of the upper gastrointestinal tract) and rectally (for radiation proctitis).

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 dimers of 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.

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. In addition to its involvement in signal transduction, -(+)-turanose can also be used as a carbon source by many organisms including numerous species of bacteria and fungi.

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.

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.

Melibiose is a reducing disaccharide formed by an α-1,6 linkage between galactose and glucose (D-Gal-(α1→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).

chemical compound

Sophorose is a disaccharide, a dimer of glucose. It differs from other glucose dimers such as maltose in having an unusual β-1,2 bond. It was isolated in 1938 from pods of Sophora japonica. It is a component of sophorolipids. It is a product of the caramelization of glucose.

Neohesperidose is the disaccharide which is present in some flavonoids. It can be found in species of Typha.

chemical compound

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.

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.

Kojibiose is a disaccharide. It is a product of the caramelization of glucose. It is also present in honey (approx. 3%).

Xylobiose is a disaccharide of xylose monomers with a beta-1,4-bond between them.

Sambubiose is a disaccharide. It is the β-D-xylosyl-(1→2)-β-D-glucose.

chemical compound

Galactose-α-1,3-galactose, commonly known as alpha gal and the Galili antigen, is a carbohydrate found in most mammalian cell membranes. It is not found in catarrhines, including humans, who have lost the glycoprotein alpha-1,3-galactosyltransferase (GGTA1) gene. Their immune systems recognize it as a foreign substance and produce xenoreactive immunoglobulin M (IgM) antibodies, leading to organ rejection after transplantation.

Robinose is a disaccharide composed of 6″-O-α-rhamnopyranosyl-β-galactopyranoside. The sugar can be found in Acalypha hispida.

Vicianose is a disaccharide.

3α-Mannobiose is a disaccharide composed of two mannose molecules connected by α(1→3) glycosidic bond.

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.

thumb|200px|right|Glucosamine dissaccharide form of chitobiose thumb|200px|right|N,N'-diacetylglucosamine dimer form of chitobiose