MetaCyc Pathway: pinitol biosynthesis I
Inferred from experiment

Pathway diagram: pinitol biosynthesis I

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: BiosynthesisCarbohydrates BiosynthesisSugars BiosynthesisSugar Alcohols BiosynthesisPinitol 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

Created 02-Mar-2011 by Zhang P, TAIR


Dittrich72: Dittrich, P, Kandler, O (1972). "Biosynthesis of D-1-O-methyl-mucoinositol in gymnosperms." Phytochemistry, 1972, 11:1729-1732.

Vernon92: Vernon DM, Bohnert HJ (1992). "A novel methyl transferase induced by osmotic stress in the facultative halophyte Mesembryanthemum crystallinum." EMBO J 11(6);2077-85. PMID: 1600940

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Ruis69: Ruis H, Hoffmann-Ostenhof O (1969). "Enzymic epimerization of sequoyitol to D-pinitol in Trifolium incarnatum." Eur J Biochem 7(3);442-8. PMID: 4389340

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.5 on Fri Nov 27, 2015, BIOCYC14A.