title: A new alternative non-mevalonate pathway for isoprenoid biosynthesis in eubacteria and plants.
abstract: Data concerning the discovery of an alternative non-mevalonate pathway for isoprenoid biosynthesis leading to isopentenyl diphosphate formation are reviewed. This pathway has been discovered in experiments with several eubacteria producing triterpenoids of the hopane series. 13C-labeled acetate, glucose, and triose phosphates were used as precursors. The 13C-labeling patterns in isoprenoids were studied by 13C-NMR spectrometry. In eubacteria the universal C5 precursor--isopentenyl diphosphate--did not appear to form via the classical acetate/mevalonate pathway, but via a novel glyceraldehyde 3-phosphate/pyruvate pathway. It is postulated that the condensation of the C2 unit formed as a result of pyruvate decarboxylation with the C3 unit (glyceraldehyde 3-phosphate) and the next transposition leads to the formation of the branched C5 precursor--isopentenyl diphosphate. In Scenedesmus obliquus not only all plastid isoprenoids (carotenoids and prenyl side chains of chlorophylls and plastoquinone-9) were formed via this novel pathway, but also the non-plastid cytoplasmic sterols. In higher plants the plastid isoprenoids were formed via the glyceraldehyde 3-phosphate/pyruvate pathway, while the cytoplasmic sterols were formed via the acetate/mevalonate pathway.
authors.affiliation: Bakh Institute of Biochemistry, Russian Academy of Sciences, Leninskii pr. 33, Moscow, 117071 Russia.
authors.forename: V A
authors.initials: VA
authors.lastname: Paseshnichenko
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D000460:Chlorophyta / Q000378:metabolism; D045782:Hemiterpenes; D008798:Mevalonic Acid / Q000378:metabolism*; D008956:Models, Chemical; D009943:Organophosphorus Compounds / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D013729:Terpenes / Q000378:metabolism*
chemical_list: D045782:Hemiterpenes; D009943:Organophosphorus Compounds; D013729:Terpenes; C004809:isopentenyl pyrophosphate; D008798:Mevalonic Acid