Mannose
| Mannose | |
|---|---|
 D-Mannopyranose
|
|
 Fischer projections
|
|
| Identifiers | |
| CAS number | 31103-86-3  |
| PubChem | 18950 |
| UNII | PHA4727WTP  |
| MeSH | Mannose |
| ChEMBL | CHEMBL469448 |
| Properties | |
| Molecular formula | C6H12O6 |
| Molar mass | 180.16 g mol−1 |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
|
| Infobox references | |
Mannose is a sugar monomer of the aldohexose series of carbohydrates. Mannose is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation are associated with mutations in enzymes involved in mannose metabolism.[1]
Contents |
Structure [edit]
Two of the cyclic mannose isomers possess a pyranose (six-membered) ring, while the other two possess a furanose (five-membered) ring.
| D-Mannose isomers | |
|---|---|
| Haworth projections | |
 α-D-Mannofuranose <1 % |
 β-D-Mannofuranose <1 % |
 α-D-Mannopyranose 67 % |
 β-D-Mannopyranose 33 % |
Metabolism [edit]
While much of the mannose used in glycosylation is believed to be derived from glucose, in cultured hepatoma (liver-derived) cells, most of the mannose for glycoprotein biosynthesis comes from extracellular mannose, not glucose.[2] Many of the glycoproteins produced in the liver are secreted into the bloodstream, so dietary mannose is distributed throughout the body. [3]
Mannose is present in numerous glycoconjugates including N-linked glycosylation of proteins. C-mannosylation is also abundant and can be found in collagen-like regions.
The digestion of many polysaccharides and glycoproteins yields mannose which is phosphorylated by hexokinase to generate mannose-6-phosphate. Mannose-6-phosphate is converted to fructose-6-phosphate, by the enzyme phosphomannose isomerase, and then enters the glycolytic pathway or is converted to glucose-6-phosphate by the gluconeogenic pathway of hepatocytes.
Biotechnology [edit]
Recombinant proteins produced in yeast may be subject to mannose addition in patterns different from those used by mammalian cells.[4] This difference in recombinant proteins from those normally produced in mammalian organisms may influence the effectiveness of vaccines.
Formation [edit]
Mannose can be formed by the oxidation of mannitol.
It can also be formed from glucose in the Lobry-de Bruyn-van Ekenstein transformation.
Etymology [edit]
The root of both "mannose" and "mannitol" is manna, which the Bible records as the food supplied to the Israelites during their journey in the region of Sinai. Several trees and shrubs can produce a substance called manna, such as the "manna tree" (Fraxinus ornus) from whose secretions mannitol was originally isolated.
Configuration [edit]
Mannose differs from glucose by inversion of the C-2 chiral center. Mannose displays a 
pucker in the solution ring form.
This apparently simple change leads to the drastically different biochemistry of the two hexoses, as it does the remaining six aldohexoses.
See also [edit]
References [edit]
- ^ Freeze, H. H.; Sharma, V. (2010). "Metabolic manipulation of glycosylation disorders in humans and animal models". Seminars in Cell & Developmental Biology 21 (6): 655–662. doi:10.1016/j.semcdb.2010.03.011. PMC 2917643. PMID 20363348.
- ^ Alton, G.; Hasilik, M.; Niehues, R.; Panneerselvam, K.; Etchison, J. R.; Fana, F.; Freeze, H. H. (1998). "Direct utilization of mannose for mammalian glycoprotein biosynthesis". Glycobiology 8 (3): 285–295. doi:10.1093/glycob/8.3.285. PMID 9451038.
- ^ Davis, J. A.; Freeze, H. H. (2001). "Studies of mannose metabolism and effects of long-term mannose ingestion in the mouse". Biochimica et biophysica acta 1528 (2–3): 116–126. doi:10.1016/S0304-4165(01)00183-0. PMID 11687298.
- ^ Vlahopoulos, S.; Gritzapis, A. D.; Perez, S. A.; Cacoullos, N.; Papamichail, M.; Baxevanis, C. N. (2009). "Mannose addition by yeast Pichia Pastoris on recombinant HER-2 protein inhibits recognition by the monoclonal antibody herceptin". Vaccine 27 (34): 4704–4708. doi:10.1016/j.vaccine.2009.05.063. PMID 19520203.
|
|||||||||||||||||||||||||||||||||||||
