This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Degradation/Utilization/Assimilation → Carbohydrates Degradation → Sugars Degradation|
|Degradation/Utilization/Assimilation → Secondary Metabolites Degradation → Sugar Derivatives Degradation → Sugar Alcohols Degradation|
Expected Taxonomic Range: Tracheophyta
Of the ten existing hexitols ( allitol, D-altritol, L-altritol, D-sorbitol, L-sorbitol, D-mannitol, L-mannitol, D-Iditol, L-iditol and galactitol) only three occur naturally - D-mannitol, D-sorbitol (also known as D-glucitol), and galactitol (owing to symmetry, D- and L-galactitol are identical). D-mannitol is the most abundant polyol in nature, and is found in bacteria, fungi, algae, lichens and vascular plants.
Many higher plants are known to contain mannitol. In several plant species (including Apium graveolens (celery), Ligustrum vulgare L. (privet), Fraxinus Americana L. (white ash), and Syringa vulgaris L. (lilac)mannitol is a major photoassimilate that is translocated through the phloem and stored in various sink tissues. Mannitol is thought to serve as a C storage compound or for storage of reducing power due to its capacity to be oxidized to its respective aldose or ketose sugar in a process that generates NADH [Stoop92, Loescher87, Stacey], thus giving a higher net ATP yield than the catabolism of an equal amount of sucrose [Pharr95].
In vascular plants, mannitol is oxidized directly to mannose by the catalytic activity of NAD-dependent mannitol dehydrogenase (MTD; to date, the best characterized enzyme of the pathway [Zamski01]), a 1-oxidoreductase. This enzyme differs from microbial mannitol dehydrogenases which are 2-oxidoreductases converting mannitol or mannitol-1-phosphate to fructose or fructose-6-phosphate, respectively. MTD catalyzes the first committed step of translocated mannitol to the central metabolism.
Pharr95: Pharr D.M., Stoop J.M.H., Williamson J.D., Studer Feusi M.E., Massel M.O., Conkling M.A. "The dual role of mannitol as osmoprotectant and photoassimilate in celery." Hort. Science (1995) 30 : 1182-1188.
Stoop92: Stoop JM, Pharr DM (1992). "Partial purification and characterization of mannitol: mannose 1-oxidoreductase from celeriac (Apium graveolens var. rapaceum) roots." Arch Biochem Biophys 298(2);612-9. PMID: 1416989
Zamski01: Zamski E, Guo WW, Yamamoto YT, Pharr DM, Williamson JD (2001). "Analysis of celery (Apium graveolens) mannitol dehydrogenase (Mtd) promoter regulation in Arabidopsis suggests roles for MTD in key environmental and metabolic responses." Plant Mol Biol 47(5);621-31. PMID: 11725947
Empadinhas01: Empadinhas N, Marugg JD, Borges N, Santos H, da Costa MS (2001). "Pathway for the synthesis of mannosylglycerate in the hyperthermophilic archaeon Pyrococcus horikoshii. Biochemical and genetic characterization of key enzymes." J Biol Chem 276(47);43580-8. PMID: 11562374
Gao05: Gao H, Yu Y, Leary JA (2005). "Mechanism and kinetics of metalloenzyme phosphomannose isomerase: measurement of dissociation constants and effect of zinc binding using ESI-FTICR mass spectrometry." Anal Chem 77(17);5596-603. PMID: 16131071
Gao05a: Gao H, Chen Y, Leary JA (2005). "Kinetic measurements of phosphoglucose isomerase and phosphomannose isomerase by direct analysis of phosphorylated aldose-ketose isomers using tandem mass spectrometry." International Journal of Mass Spectrometry 240(3);291-299.
Giese05: Giese JO, Herbers K, Hoffmann M, Klosgen RB, Sonnewald U (2005). "Isolation and functional characterization of a novel plastidic hexokinase from Nicotiana tabacum." FEBS Lett 579(3);827-31. PMID: 15670855
Kang67: Kang S, Markovitz A (1967). "Induction of capsular polysaccharide synthesis by rho-fluorophenylalanine in Escherichia coli wild type and strains with altered phenylalanyl soluble ribonucleic acid synthetase." J Bacteriol 93(2);584-91. PMID: 5335965
Lee84: Lee B.T., Matheson N.K. "Phosphomannoisomerase and phosphoglucoisomerase in seeds of Cassia coluteoides and some other legumes that synthesize galactomannan." Phytochemistry (1984) 23(5) : 983-987.
Markovitz67: Markovitz A, Sydiskis RJ, Lieberman MM (1967). "Genetic and biochemical studies on mannose-negative mutants that are deficient in phosphomannose isomerase in Escherichia coli K-12." J Bacteriol 94(5);1492-6. PMID: 4862193
Roux11: Roux C, Bhatt F, Foret J, de Courcy B, Gresh N, Piquemal JP, Jeffery CJ, Salmon L (2011). "The reaction mechanism of type I phosphomannose isomerases: new information from inhibition and polarizable molecular mechanics studies." Proteins 79(1);203-20. PMID: 21058398
Shinabarger91: Shinabarger D, Berry A, May TB, Rothmel R, Fialho A, Chakrabarty AM (1991). "Purification and characterization of phosphomannose isomerase-guanosine diphospho-D-mannose pyrophosphorylase. A bifunctional enzyme in the alginate biosynthetic pathway of Pseudomonas aeruginosa." J Biol Chem 266(4);2080-8. PMID: 1846611
Williamson95: Williamson JD, Stoop JM, Massel MO, Conkling MA, Pharr DM (1995). "Sequence analysis of a mannitol dehydrogenase cDNA from plants reveals a function for the pathogenesis-related protein ELI3." Proc Natl Acad Sci U S A 92(16);7148-52. PMID: 7638158
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