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:||Biosynthesis → Carbohydrates Biosynthesis → Sugars Biosynthesis → Sugar Alcohols Biosynthesis → Pinitol Biosynthesis|
Some taxa known to possess this pathway include : Mesembryanthemum crystallinum
Expected Taxonomic Range: Viridiplantae
Pinitol is a methylated cyclic sugar alcohol (cyclitol). It has been found in bacteria, fungi, algae and plants. It plays an important role in osmoregulation and osmoprotection. In the salt-tolerant plant M. crystallinum (common ice plant), pinitol can accumulate up to 70% of total soluble carbohydrate, or 10% of plant dry weight under water stress conditions. In salt-tolerant plants pinitol was found located in the cytosol and chloroplast. In angiosperms, pinitol biosynthesis proceeds via ononitol (1D-4-O-methyl myo-inositol) [Vernon92], whereas in gymnosperms, it proceeds via sequoyitol (1D-5-O-methyl myo-inositol) [Dittrich72].
Epimerization of ononitol to pinitol is likely to proceed via a keto intermediate, similar to the case of epimerization of sequoyitol in pinitol biosynthesis II.
Variants: pinitol biosynthesis II
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