5-Deoxyinositol Explained

5-Deoxyinositol (quercitol) is a cyclitol. It can be found in wines aged in oak wood barrels.[1] It can also be found in Quercus sp. (oaks)[2] and in Gymnema sylvestre. It is different from, a synonym of quercetin.

Biosynthesis

The proposed biosynthesis of 5-deoxyinositol begins with the conversion of D-glucose to myo-inositol.[3] In this pathway, D-glucose is phosphorylated to form D-glucose-6-phosphate. The NAD+ dependent enzyme inositol 1-phosphate synthase (I1PS) then catalyzes the subsequent oxidation, enolization, aldol cyclization, and reduction of D-glucose 6-phosphate to form myo-inositol 1-phosphate. Hydrolysis of the phosphate group on this molecule gives myo-inositol. Myo-inositol can then be converted into 5-deoxyinositol in three steps,[4] beginning with the oxidation of myo-inositol by inositol dehydrogenase (ID) to form scyllo-inosose. This intermediate is then dehydrated to form a diketone. The reduction of this diketone gives 5-deoxyinositol. This final reduction is thought to be catalyzed by one or more unidentified reductases or dehydrogenases.

Notes and References

  1. Occurrence and Significance of Quercitol and Other Inositols in Wines during Oak Wood Aging . Davinia Carlavilla . Mar Villamiel . Isabel Martínez-Castro . M. Victoria Moreno-Arribas . amp . Am. J. Enol. Vitic. . 57 . 4 . 468–473 . 2006. 10.5344/ajev.2006.57.4.468 . 83679744 .
  2. Analysis of cyclitols in different Quercus species by gas chromatography–mass spectrometry . Sonia Rodríguez-Sánchez . Ana I Ruiz-Matute . María Elena Alañón. María Soledad Pérez-Coello . Luis F de Julio-Torres. Ramón Morales . Isabel Martínez-Castro . amp . Journal of the Science of Food and Agriculture . 90 . 10 . 1735–1738 . 2010 . 10.1002/jsfa.4009. 20564438 . 2010JSFA...90.1735R .
  3. Majumder . A. L. . Johnson . M. D. . Henry . S. A. . 1997-09-04 . 1L-myo-inositol-1-phosphate synthase . Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism . 1348 . 1–2 . 245–256 . 10.1016/s0005-2760(97)00122-7 . 0006-3002 . 9370339.
  4. Yoshida . Ken-ichi . Yamaguchi . Masanori . Morinaga . Tetsuro . Kinehara . Masaki . Ikeuchi . Maya . Ashida . Hitoshi . Fujita . Yasutaro . 2008-04-18 . myo-Inositol catabolism in Bacillus subtilis . The Journal of Biological Chemistry . 283 . 16 . 10415–10424 . 10.1074/jbc.M708043200 . 0021-9258 . 18310071. free .