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l-Glucose is an organic compound with formula C 6 H 12 O 6 or O=CH[CH(OH)] 5 H, specifically one of the aldohexose monosaccharides. As the l-isomer of glucose, it is the enantiomer of the more common d-glucose. l-Glucose does not occur naturally in living organisms, but can be synthesized in the laboratory.
The aldohexose that is most important in biochemistry is D-glucose, which is the main "fuel" for metabolism in many living organisms. The 2-ketohexoses psicose, fructose and tagatose occur naturally as the D-isomers, whereas sorbose occurs naturally as the L-isomer. D-Sorbose is commonly used in the commercial synthesis of ascorbic acid. [10]
The fact that d-glucose is dextrorotatory is a combined effect of its four chiral centres, not just of C-5; some of the other d-aldohexoses are levorotatory. The conversion between the two anomers can be observed in a polarimeter since pure α-d-glucose has a specific rotation angle of +112.2° mL/(dm·g), pure β-d-glucose of +17.5° mL/(dm·g ...
The table sugar used in everyday vernacular is itself a disaccharide sucrose comprising one molecule of each of the two monosaccharides D-glucose and D-fructose. [2] Each carbon atom that supports a hydroxyl group is chiral, except those at the end of the chain. This gives rise to a number of isomeric forms, all with the same chemical formula.
The lowercase "d-" and "l-" prefixes are distinct from the SMALL CAPS "D-" and "L-" prefixes. The " D -" and " L -" prefixes are used to specify the enantiomer of chiral organic compounds in biochemistry and are based on the compound's absolute configuration relative to (+)- glyceraldehyde , which is the D -form by definition.
For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde.[note 1] However, L-arabinose is in fact more common than D-arabinose in nature and is found in nature as a component of biopolymers such as hemicellulose and pectin.
Two enantiomers are possible, d-ribulose (d-erythro-pentulose) and l-ribulose (l-erythro-pentulose). d-Ribulose is the diastereomer of d-xylulose. Ribulose sugars are composed in the pentose phosphate pathway from arabinose. [1] They are important in the formation of many bioactive substances. For example, d-ribulose is an intermediate in the ...
Fucose is a hexose deoxy sugar with the chemical formula C 6 H 12 O 5. It is found on N-linked glycans on the mammalian, insect and plant cell surface. Fucose is the fundamental sub-unit of the seaweed polysaccharide fucoidan. [1] The α(1→3) linked core of fucoidan is a suspected carbohydrate antigen for IgE-mediated allergy. [2]