Mannose
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| Mannose | |
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| Identifiers | |
| CAS number | [31103-86-3] |
| PubChem | |
| MeSH | |
| Properties | |
| Molecular formula | C6H12O6 |
| Molar mass | 180.156 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Mannose is a sugar monomer of the hexose series of carbohydrates.
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[edit] Metabolism
Mannose enters the carbohydrate metabolism stream in two steps:
- First it undergoes phosphorylation to mannose-6-phosphate by hexokinase.
- Then, it is converted to fructose-6-phosphate by mannose phosphate isomerase.
Mannose is present in numerous glycoconjugates including N-linked glycosylation of proteins. C-mannosylation is also abundant and can be found in collage-like regions. Mannose is a C2 epimer of glucose and displays a ^2C_4 pucker in the solution ring form.
[edit] Formation
Mannose can be formed by the oxidation of mannitol.
It can also be formed from D-glucose in the Lobry-de Bruyn-van Ekenstein transformation
[edit] Etymology
The root of both "mannose" and "manitol" is manna, which the Bible records as the food supplied to the Israelites during their journey through the Sinai Peninsula. Manna is a sweet secretion of several trees and shrubs, such as Fraxinus ornus.
[edit] Cranberry juice
D-Mannose, which appears in some fruits including cranberry, has been postulated to prevent the adhesion of bacteria to the epithelium of the urinary tract and Urinary bladder through a mechanism presumed to be competitive in nature with the polysaccharide coating of the cystic epithelium. While no studies have objectively verified this mechanism, anecdotal reports from patients show some improvement in symptoms.[1][2]
[edit] Configuration
The fact that D-mannose has the same configuration at its penultimate carbon as D-glyceraldehyde is unsurprising as that is what defines the dextro classification. However, mannose differs from D-glucose by inversion of the C2 chiral centre. This apparently simple change leads to the drastically different chemistry of the two hexoses, as it does the remaining six hexoses.
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