Mannose

Mannose
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Identifiers
CAS number	31103-86-3
PubChem	18950
MeSH	Mannose
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

File:DL-Mannose.svg

D and L forms

Haworth projection of mannose in its α-D-mannopyranose form.

Mannose is a sugar monomer of the hexose series of carbohydrates.

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.

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

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.

Cranberry juice

D-Mannose, which appears in some fruits including cranberry, has been shown to prevent the adhesion of bacteria to tissues of the urinary tract and bladder.

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.

Mnemonic

The hexoses can be remembered conveniently by the following phrase:

"All (allose) altruists (altrose) gladly (glucose) make (mannose) gum (gulose) in (idose) gallon (galactose) tanks (talose)."

See also

• Glycosylation
• alpha-Mannosidase
• Hexose
• Mannose receptor