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D-chiro-Inositol (also known as 1D-chiro-inositol, abbreviated DCI) is an inositol isoform. Inositol is a derivative of cyclohexane with six hydroxyl groups, making it a polyol. It also is known as a sugar alcohol, having exactly the same molecular formula as glucose or other hexoses. Inositol exists in nine possible stereoisomers, including scyllo-inositol, myo-inositol (the most abundant), muco-inositol, D-chiro-inositol, L-chiro-inositol, neo-inositol, allo-inositol, epi-inositol, and cis-inositol. myo-Inositol is converted into DCI by an insulin dependent NAD/NADH epimerase enzyme. It is known to be an important secondary messenger in insulin signal transduction. DCI accelerates the dephosphorylation of glycogen synthase and pyruvate dehydrogenase, rate limiting enzymes of non-oxidative and oxidative glucose disposal. DCI may act to bypass defective normal epimerization of myo-inositol to DCI associated with insulin resistance and at least partially restore insulin sensitivity and glucose disposal.

A derivative of D-gluconic acid lacking the 2-hydroxy group." []

Alpha-D-fructofuranose is a D-fructofuranose. It is an enantiomer of an alpha-L-fructofuranose. alpha-D-fructofuranose is a natural product found in Detarium microcarpum with data available.

D-Galactose (CAS: 59-23-4) is an aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. D-Galactose is an energy-providing nutrient and also a necessary basic substrate for the biosynthesis of many macromolecules in the body. Metabolic pathways for D-galactose are important not only for the provision of these pathways but also for the prevention of D-galactose metabolite accumulation. The main source of D-galactose is lactose in the milk of mammals, but it can also be found in some fruits and vegetables. Utilization of D-galactose in all living cells is initiated by the phosphorylation of the hexose by the enzyme galactokinase (E.C. 2.7.1.6) (GALK) to form D-galactose-1-phosphate. In the presence of D-galactose-1-phosphate uridyltransferase (E.C. 2.7.7.12) (GALT) D-galactose-1-phosphate is exchanged with glucose-1-phosphate in UDP-glucose to form UDP-galactose. Glucose-1-phosphate will then enter the glycolytic pathway for energy production. Deficiency of the enzyme GALT in galactosemic patients leads to the accumulation of D-galactose-1-phosphate. Classic galactosemia, a term that denotes the presence of D-galactose in the blood, is the rare inborn error of D-galactose metabolism, diagnosed by the deficiency of the second enzyme of the D-galactose assimilation pathway, GALT, which, in turn, is caused by mutations at the GALT gene (PMID: 15256214, 11020650, 10408771). Galactose in the urine is a biomarker for the consumption of milk.

alpha-D-Glucose, also known as alpha-dextrose or alpha-D-GLC, belongs to the class of organic compounds known as hexoses. These are monosaccharides in which the sugar unit is a is a six-carbon containing moeity. alpha-D-Glucose exists in all living species, ranging from bacteria to humans. Outside of the human body, alpha-D-Glucose has been detected, but not quantified in several different foods, such as lemon grass, sourdoughs, mixed nuts, sweet rowanberries, and ginsengs. This could make alpha-D-glucose a potential biomarker for the consumption of these foods. D-Glucopyranose having alpha-configuration at the anomeric centre.

D-Mannose (also called Mannose or D-mannopyranose) is a hexose or a six-carbon sugar. It is also classified as an aldohexose. It is fermentable monosaccharide and an isomer of glucose. Mannose commonly exists as two different-sized rings, the pyranose (six-membered) form and the furanose (five-membered) form. Formally, D-Mannose is the 2-epimer of glucose and exists primarily as sweet-tasting alpha- (67%) or as a bitter-tasting beta- (33%) anomer of the pyranose form (PMID: 24931670). Mannose is not an essential nutrient, meaning that it can be produced in the human body from glucose or converted into glucose. Mannose is ~5x as active as glucose in non-enzyamtic glycation, which may explain why evolution did not favor it as a biological energy source (PMID: 24931670). Mannose occurs in microbes, plants and animals. Free mannose is found in small amounts in many fruits such as oranges, apples and peaches and in mammalian plasma at 50–100 uM (PMID: 24931670). More often, mannose occurs in homo-or hetero-polymers such as yeast mannans (alpha-mannose) where it can account for nearly 16% of dry weight or in galactomannans. Coffee beans, fenugreek and guar gums are rich sources of galactomannans. However, these plant polysaccharides are not degraded in the mammalian GI tract and, therefore, provide very little bio-available mannose for glycan synthesis. The digestion of many polysaccharides and glycoproteins also yields mannose. Once mannose is released, it is phosphorylated by hexokinase to generate mannose-6-phosphate. Mannose-6-phosphate is then converted to fructose-6-phosphate, by the enzyme phosphomannose isomerase, whereupon it enters the glycolytic pathway or is converted to glucose-6-phosphate by the gluconeogenic pathway. Mannose is a dominant monosaccharide in N-linked glycosylation, which is a post-translational modification of proteins. N-linked glycosylation is initiated by the transfer of Glc3Man9GlcNAc2 to nascent glycoproteins in the endoplasmic reticulum in a co-translational manner as the protein enters the transport system. Typically, mature human glycoproteins only contain three mannose residues buried under sequential modification by GlcNAc, galactose, and sialic acid. High-mannose-type oligosaccharides have been shown to play important roles in protein quality control. Several intracellular proteins such as lectins, chaperones, and glycan-processing enzymes, are involved in this process. These include calnexin/calreticulin, UDP-glucose:glycoprotein glucosyltransferase (UGGT), cargo receptors (such as VIP36 and ERGIC-53), mannosidase-like proteins (e.g. EDEM and Htm1p) and ubiquitin ligase (Fbs). They are thought to recognize high-mannose-type glycans with subtly different structures. Mannose-binding lectin (MBL) is an important constituent of the innate immune system. This protein binds through multiple lectin domains to the repeating sugar arrays that decorate many microbial surfaces and is then able to activate the complement system through a specific protease called MBL-associated protease-2. Mannose (D-mannose) is used as a nutritional supplement, packaged as "D-mannose", to prevent recurrent urinary tract infections (PMID: 21105658). D-mannose prevents FimH-mediated bacterial adhesion in the urinary tract through a competitive inhibition mechanism. This mechanism is based on the structural similarity between D-mannose and urothelial mannosylated receptors exposed by the epithelium of the urinary tract (PMID: 21105658). When D-mannose is administered in sufficient amounts, it is rapidly absorbed and then excreted by the urinary tract where it saturates bacterial FimH, thereby preventing bacterial binding to urothelial cells.

L-Sorbose, also known as L-sorbinose or L-xylo-hexulose, belongs to the class of organic compounds known as monosaccharides. Monosaccharides are compounds containing one carbohydrate unit not glycosidically linked to another such unit, and no set of two or more glycosidically linked carbohydrate units. Monosaccharides have the general formula CnH2nOn. L-Sorbose exists in all living species, ranging from bacteria to humans. The commercial production of vitamin C (ascorbic acid) often begins with sorbose. L-Sorbose (CAS: 87-79-6) is a ketose belonging to the group of sugars known as monosaccharides. Sorbose has been found to be a metabolite of Ketogulonicigenium (PMID:15785002).

Fructose, or levulose, is a levorotatory monosaccharide and an isomer of glucose (C6H12O6). Pure fructose has a sweet taste similar to cane sugar, but with a "fruity" aroma. Pure, dry fructose is a sweet, white, odorless, crystalline solid, and is the most water-soluble of all the sugars. Although fructose is a hexose (6-carbon sugar), it generally exists as a 5-member hemiketal ring (a furanose). This structure is responsible for the long metabolic pathway and high reactivity compared to glucose. Fructose is a reducing sugar, as are all monosaccharides. Fructose is found in many foods including honey, tree fruits, berries, melons, and some root vegetables, such as beets, sweet potatoes, parsnips, and onions. Commercially, fructose is derived from sugar cane, sugar beets, and maize. Fructose is also derived from the digestion of sucrose, a disaccharide consisting of glucose and fructose that is broken down by enzymes during digestion. Fructose is the sweetest naturally occurring sugar, estimated to be twice as sweet as sucrose. It is used as a preservative and an intravenous infusion in parenteral feeding. Excessive consumption of fructose (especially from sugar-sweetened beverages) may contribute to insulin resistance, obesity, elevated LDL cholesterol and triglycerides, leading to metabolic syndrome (PMID: 26429086). 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. After absorption, it enters the hepatic portal vein and is directed toward the liver. fructose absorption occurs on the mucosal membrane via facilitated transport involving GLUT5 transport proteins. Since the concentration of fructose is higher in the lumen, fructose is able to flow down a concentration gradient into the enterocytes, assisted by transport proteins. Fructose may be transported out of the enterocyte across the basolateral membrane by either GLUT2 or GLUT5, although the GLUT2 transporter has a greater capacity for transporting fructose, and, therefore, the majority of fructose is transported out of the enterocyte through GLUT2. The catabolism of fructose is sometimes referred to as fructolysis. In fructolysis, the enzyme fructokinase produces fructose 1-phosphate, which is split by aldolase B to produce the trioses dihydroxyacetone phosphate (DHAP) and glyceraldehyde. Unlike glycolysis, in fructolysis the triose glyceraldehyde lacks a phosphate group. A third enzyme, triokinase, is therefore required to phosphorylate glyceraldehyde, producing glyceraldehyde 3-phosphate. The resulting trioses can enter the gluconeogenic pathway for glucose or glycogen synthesis, or be further catabolized through the lower glycolytic pathway to pyruvate. Fructose metabolism leads to significant increases of plasma uric acid levels (PMID: 28420204). In fructolysis, fructose 1-phosphate accumulates, and intracellular phosphate decreases. This decrease stimulates AMP deaminase (AMPD), which catalyzes the degradation of AMP to inosine monophosphate, increasing the rate of purine degradation (PMID: 28420204). The purine degradation produces uric acid and generates mitochondrial oxidants. Mitochondrial oxidative stress then induces aconitase inhibition in the Krebs cycle, with accumulation of citrate and stimulation of ATP citrate lyase and fatty acid synthase (PMID: 28420204). The result is de novo lipogenesis and hepatic fat accumulation. Physiologically, the increase in intracellular uric acid is followed by an acute rise in circulating levels of uric acid, which is likely due to its release from the liver. Fructose also stimulates uric acid synthesis from amino acid precursors such as glycine. Moreover, long-term fructose administration suppresses renal excretion of uric acid, resulting in elevated serum uric acid levels.

Galactose is an optical isomer of glucose. An aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. Deficiency of galactosyl-1-phosphate uridyltransferase (Galactose-1-phosphate uridyl-transferase deficiency disease) causes an error in galactose metabolism called galactosemia, resulting in elevations of galactose in the blood. Galactose (Gal) (also called brain sugar) is a type of sugar found in dairy products, in sugar beets and other gums and mucilages. It is also synthesized by the body, where it forms part of glycolipids and glycoproteins in several tissues. It is considered a nutritive sweetener because it has food energy. Galactose is less sweet than glucose and not very water-soluble. Galactose is a monosaccharide constituent, together with glucose, of the disaccharide lactose. The hydrolysis of lactose to glucose and galactose is catalyzed by the enzyme beta-galactosidase, a lactase. In the human body, glucose is changed into galactose in order to enable the mammary glands to secrete lactose. Galactan is a polymer of the sugar galactose. It is found in hemicellulose and can be converted to galactose by hydrolysis.

Glucose is a monosaccharide containing six carbon atoms and an aldehyde group. It is referred to as an aldohexose. The glucose molecule can exist in an open-chain (acyclic) and ring (cyclic) form, the latter being the result of an intramolecular reaction between the aldehyde C atom and the C-5 hydroxyl group to form an intramolecular hemiacetal. In aqueous solution, both forms are in equilibrium and at pH 7 the cyclic one is predominant. Glucose is a primary source of energy for all living organisms. It is a fundamental metabolite found in all organisms, ranging from bacteria to plants to humans. Most of the world’s glucose is made by plants and algae during photosynthesis from water and carbon dioxide, where it is used to make cellulose (and other polymeric forms of glucose called polysaccharides) that stabilize plant cell walls. Glucose is also found in fruits and other parts of plants in its free state. In animals, glucose can be generated from the breakdown of glycogen in a process known as glycogenolysis. Glucose can also be synthesized de novo in animals. In particular it can be synthesized in the liver and kidneys from non-carbohydrate intermediates, such as pyruvate and glycerol, by a process known as gluconeogenesis. Humans also consume large amounts of glucose as part of their regular diet. Ingested glucose initially binds to the receptor for sweet taste on the tongue in humans. This complex of the proteins T1R2 and T1R3 makes it possible to identify glucose-containing food sources. Glucose in the body mainly comes from food - about 300 g per day for the average adult. In humans, the breakdown of glucose-containing polysaccharides happens partly during chewing by means of the enzyme known as amylase, which is contained in saliva, as well as by other enzymes such as maltase, lactase and sucrase on the brush border of the small intestine. The blood sugar content of a healthy person in the short-time fasting state, e.g. after overnight fasting, is about 70 to 100 mg/dL of blood (4 to 5.5 mM). In blood plasma, the measured values are about 10–15% higher. Dysregulated metabolism of glucose can lead to a number of diseases including diabetes. Diabetes is a metabolic disorder where the body is unable to regulate levels of glucose in the blood either because of a lack of insulin in the body or the failure, by cells in the body, to respond properly to insulin. Each of these situations can be caused by persistently high elevations of blood glucose levels, through pancreatic burnout and insulin resistance.

A D-mannopyranose in which the anomeric centre has beta configuration." []

Allose is an aldohexose sugar. Allose is a C-3 epimer of glucose. D-allose is a rare sugar found in nature and, because of its very limited amount and of the high cost associated with its synthesis, its physiological functions remain virtually unknown (PMID 16080505). It is believed to have inhibitory effect on cancer cell proliferation (PMID 16142305), protective effects against ischemia reperfusion injury (PMID 14605979, 16716947), immunosuppressant on allogenic orthotopic liver transplantation (PMID 11120048), neuroprotective effects against retinal ischemia (PMID 16565406), suppress development of salt-induced hypertension (PMID 16148613) and an inhibitory effect on human ovarian carcinoma cells (PMID 16080505). It is a rare monosaccharide that has been isolated from the leaves of the African shrub Protea rubropilosa. It is soluble in water and practically insoluble in methanol.

An altrose that has D- configuration." []

Fructose is a levorotatory monosaccharide and an isomer of glucose. Although fructose is a hexose (6 carbon sugar), it generally exists as a 5-member hemiketal ring (a furanose)." []

D-fructopyranose is a fructopyranose having D-configuration. It has a role as a sweetening agent. It is a fructopyranose, a D-fructose and a cyclic hemiketal. D-Fructose is a metabolite found in or produced by Escherichia coli (strain K12, MG1655). D-Fructose is a natural product found in Maclura pomifera, Rehmannia glutinosa, and other organisms with data available. A monosaccharide in sweet fruits and honey that is soluble in water, alcohol, or ether. It is used as a preservative and an intravenous infusion in parenteral feeding.

The open-chain form of D-fructose." []

D-fuconic acid is a fuconic acid. It is a conjugate acid of a D-fuconate. See also: D-Fuconate (annotation moved to).