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.
Synonyms: tocopherol biosynthesis
|Superclasses:||Biosynthesis → Cofactors, Prosthetic Groups, Electron Carriers Biosynthesis → Quinol and Quinone Biosynthesis|
|Biosynthesis → Cofactors, Prosthetic Groups, Electron Carriers Biosynthesis → Vitamins Biosynthesis|
Structurally tocotrienols and tocopherols differ only in the degree of unsaturation of their side-chain. The tocotrienol chain comprises three trans-double bonds, whereas the tocopherol chain is fully saturated. In addition, the α, β, γ, and δ species of both compound groups vary in the methylation pattern of the chromanol ring [Cahoon03].
Vitamin E compounds are synthesized only by photosynthetic organisms, although they are essential dietary components for animals (including humans), where they act primarily as antioxidants. Their presumed role in plants involve protection of chloroplast lipids and chlorophylls against oxidative damages. The tocotrienols are mostly found in monocots [Padley94] and a few dicots [Horvath], whereas tocopherols are wider spread in the plant kingdom and dominate in the dicots [KamalEldin96].
The tocopherols include α-tocopherol, β-tocopherol, γ-tocopherol and δ-tocopherol, which differ only in the number and position of methyl groups on the chromanol ring. α-tocopherol has been shown to possess the highest vitamin E activity.
The genes encoding all the of pathway enzymes have been cloned from Arabidopsis.
Unification Links: AraCyc:PWY-1422
Cahoon03: Cahoon EB, Hall SE, Ripp KG, Ganzke TS, Hitz WD, Coughlan SJ (2003). "Metabolic redesign of vitamin E biosynthesis in plants for tocotrienol production and increased antioxidant content." Nat Biotechnol 21(9);1082-7. PMID: 12897790
Cheng03a: Cheng Z, Sattler S, Maeda H, Sakuragi Y, Bryant DA, DellaPenna D (2003). "Highly divergent methyltransferases catalyze a conserved reaction in tocopherol and plastoquinone synthesis in cyanobacteria and photosynthetic eukaryotes." Plant Cell 15(10);2343-56. PMID: 14508009
Horvath: Horvath G, Wessjohann L, Bigirimana J, Monica H, Jansen M, Guisez Y, Caubergs R, Horemans N "Accumulation of tocopherols and tocotrienols during seed development of grape (Vitis vinifera L. cv. Albert Lavallee)." Plant Physiol Biochem 44(11-12);724-31. PMID: 17110122
Porfirova02: Porfirova S, Bergmuller E, Tropf S, Lemke R, Dormann P (2002). "Isolation of an Arabidopsis mutant lacking vitamin E and identification of a cyclase essential for all tocopherol biosynthesis." Proc Natl Acad Sci U S A 99(19);12495-500. PMID: 12213958
Albermann08: Albermann C, Ghanegaonkar S, Lemuth K, Vallon T, Reuss M, Armbruster W, Sprenger GA (2008). "Biosynthesis of the vitamin E compound delta-tocotrienol in recombinant Escherichia coli cells." Chembiochem 9(15);2524-33. PMID: 18810749
Brownlee04: Brownlee JM, Johnson-Winters K, Harrison DH, Moran GR (2004). "Structure of the ferrous form of (4-hydroxyphenyl)pyruvate dioxygenase from Streptomyces avermitilis in complex with the therapeutic herbicide, NTBC." Biochemistry 43(21);6370-7. PMID: 15157070
Collakova01: Collakova E, DellaPenna D (2001). "Isolation and functional analysis of homogentisate phytyltransferase from Synechocystis sp. PCC 6803 and Arabidopsis." Plant Physiol 127(3);1113-24. PMID: 11706191
Dahnhardt02: Dahnhardt D, Falk J, Appel J, van der Kooij TA, Schulz-Friedrich R, Krupinska K (2002). "The hydroxyphenylpyruvate dioxygenase from Synechocystis sp. PCC 6803 is not required for plastoquinone biosynthesis." FEBS Lett 523(1-3);177-81. PMID: 12123828
Garcia00: Garcia I, Job D, Matringe M (2000). "Inhibition of p-hydroxyphenylpyruvate dioxygenase by the diketonitrile of isoxaflutole: a case of half-site reactivity." Biochemistry 39(25);7501-7. PMID: 10858299
Garcia99: Garcia I, Rodgers M, Pepin R, Hsieh TF, Matringe M (1999). "Characterization and subcellular compartmentation of recombinant 4-hydroxyphenylpyruvate dioxygenase from Arabidopsis in transgenic tobacco." Plant Physiol 119(4);1507-16. PMID: 10198110
Gunsior04: Gunsior M, Ravel J, Challis GL, Townsend CA (2004). "Engineering p-hydroxyphenylpyruvate dioxygenase to a p-hydroxymandelate synthase and evidence for the proposed benzene oxide intermediate in homogentisate formation." Biochemistry 43(3);663-74. PMID: 14730970
Koch03: Koch M, Lemke R, Heise KP, Mock HP (2003). "Characterization of gamma-tocopherol methyltransferases from Capsicum annuum L and Arabidopsis thaliana." Eur J Biochem 270(1);84-92. PMID: 12492478
Lipka13: Lipka AE, Gore MA, Magallanes-Lundback M, Mesberg A, Lin H, Tiede T, Chen C, Buell CR, Buckler ES, Rocheford T, DellaPenna D (2013). "Genome-wide association study and pathway-level analysis of tocochromanol levels in maize grain." G3 (Bethesda) 3(8);1287-99. PMID: 23733887
Motohashi03: Motohashi R, Ito T, Kobayashi M, Taji T, Nagata N, Asami T, Yoshida S, Yamaguchi-Shinozaki K, Shinozaki K (2003). "Functional analysis of the 37 kDa inner envelope membrane polypeptide in chloroplast biogenesis using a Ds-tagged Arabidopsis pale-green mutant." Plant J 34(5);719-31. PMID: 12787252
Norris98: Norris SR, Shen X, DellaPenna D (1998). "Complementation of the Arabidopsis pds1 mutation with the gene encoding p-hydroxyphenylpyruvate dioxygenase." Plant Physiol 117(4);1317-23. PMID: 9701587
Sattler03: Sattler SE, Cahoon EB, Coughlan SJ, DellaPenna D (2003). "Characterization of tocopherol cyclases from higher plants and cyanobacteria. Evolutionary implications for tocopherol synthesis and function." Plant Physiol 132(4);2184-95. PMID: 12913173
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