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: benzoate biosynthesis (non-oxidative), benzoic acid biosynthesis
|Superclasses:||Biosynthesis → Secondary Metabolites Biosynthesis → Phenylpropanoid Derivatives Biosynthesis → Benzenoids Biosynthesis → Benzoate Biosynthesis|
Expected Taxonomic Range: Embryophyta
Benzoic acid, derived from phenylalanine, is a precuror to several important benzenoid compounds, including floral scent constituents, such as phenylethylbenzoate, benzylbenzoate methyl benzoate [Boatright04, Azuma02, DAuria02, Negre02]; the defense signaling compounds salicylic acid (SA) and its derivatives [Vlot09, Lu09a], and a number of pharmacologically active compounds, such as taxol [Walker00a] (rev in [Wildermuth06]). An important step in the creation of benzoic acid is the cleavage of two carbon atoms from the 3-carbon side-chain present on trans-cinnamic acid. At least three different chain-shortening routes have been proposed in plants [Boatright04] and there is evidence that a subset of the different pathways may operate in individual species, and may differentially contribute to benzoic acid biosynthesis within each species. For example, Petunia x hybrida has at least two pathways present (this pathway and benzoate biosynthesis I (CoA-dependent, β-oxidative)), whereas cucumber (Cucumis sativus) and Nicotiana attenuata seem to lack this variant [Jarvis00] and Hypericum androsaemum relies on a third pathway (benzoate biosynthesis III (CoA-dependent, non-β-oxidative)) that incorporates elements of the other two variants.
A greater understanding of the metabolic pathways involved in benzoic acid biosynthesis may contribute to genetic engineering efforts aimed at altering floral scents, modifying SA-based defense responses, and increasing the production of pharmaceutically important compounds [Pichersky07, Xiang07].
Although benzoate biosynthesis has been primarily studied in plants, there is evidence that Streptomyces maritimus bacteria make benzoyl-CoA using the early steps in the benzoate biosynthesis I (CoA-dependent, β-oxidative) pathway [Moore02b].
About This Pathway
In this pathway, the chain shortening is accomplished through the removal of an acetate in the third reaction giving rise to benzaldehyde. Although this compound does not function as an intermediate in the benzoate biosynthesis I (CoA-dependent, β-oxidative) pathway, the characterization of benzaldehyde dehydrogenases in snapdragon and Arabidopsis indicate that benzoic acid can be generated from this precursor in a subset of plant species [Long09, Ibdah09].
PAL, the enzyme catalyzing the first step in this reaction is subject to regulation in many plant species and thus controls the flux through many secondary metabolic biosynthetic pathways. More specific regulation may be achieved in this pathway through fine-tuned expression of downstream enzymes. For example, transcript levels of the snapdragon benzaldehyde dehydrogenase are highest in the parts of the flower that produce scent (the upper and lower petal lobes) and they also show developmental and diurnal changes that are correlated with the production of methylbenzoate and benzoic acid respectively [Long09]. On the other hand benzaldehyde dehydrogenase / benzaldehyde oxidase transcripts seem to be expressed predominantly in developing seeds in Arabdopsis [Ibdah09].
Despite years of study, little is known about the subcellular localization of various components of the benzoic acid biosynthesis pathways. The finding that the snapdragon benzaldehyde dehydrogenase localizes to the mitochondria [Long09] while the Arabidopsis benzaldehyde dehydrogenase / benzaldehyde oxidase lacks any discernable targeting signal and thus likely resides in the cytosol [Ibdah09] may further complicate efforts to study the compartmentalization of this pathway.
Unification Links: PlantCyc:PWY-6444
Boatright04: Boatright J, Negre F, Chen X, Kish CM, Wood B, Peel G, Orlova I, Gang D, Rhodes D, Dudareva N (2004). "Understanding in vivo benzenoid metabolism in petunia petal tissue." Plant Physiol 135(4);1993-2011. PMID: 15286288
DAuria02: D'Auria JC, Chen F, Pichersky E (2002). "Characterization of an acyltransferase capable of synthesizing benzylbenzoate and other volatile esters in flowers and damaged leaves of Clarkia breweri." Plant Physiol 130(1);466-76. PMID: 12226525
Ibdah09: Ibdah M, Chen YT, Wilkerson CG, Pichersky E (2009). "An aldehyde oxidase in developing seeds of Arabidopsis converts benzaldehyde to benzoic Acid." Plant Physiol 150(1);416-23. PMID: 19297586
Jarvis00: Jarvis AP, Schaaf O, Oldham NJ (2000). "3-hydroxy-3-phenylpropanoic acid is an intermediate in the biosynthesis of benzoic acid and salicylic acid but benzaldehyde is not." Planta 212(1);119-26. PMID: 11219576
Long09: Long MC, Nagegowda DA, Kaminaga Y, Ho KK, Kish CM, Schnepp J, Sherman D, Weiner H, Rhodes D, Dudareva N (2009). "Involvement of snapdragon benzaldehyde dehydrogenase in benzoic acid biosynthesis." Plant J 59(2);256-65. PMID: 19292760
Moore02b: Moore BS, Hertweck C, Hopke JN, Izumikawa M, Kalaitzis JA, Nilsen G, O'Hare T, Piel J, Shipley PR, Xiang L, Austin MB, Noel JP (2002). "Plant-like biosynthetic pathways in bacteria: from benzoic acid to chalcone." J Nat Prod 65(12);1956-62. PMID: 12502351
Negre02: Negre F, Kolosova N, Knoll J, Kish CM, Dudareva N (2002). "Novel S-adenosyl-L-methionine:salicylic acid carboxyl methyltransferase, an enzyme responsible for biosynthesis of methyl salicylate and methyl benzoate, is not involved in floral scent production in snapdragon flowers." Arch Biochem Biophys 406(2);261-70. PMID: 12361714
Walker00a: Walker K, Croteau R (2000). "Taxol biosynthesis: molecular cloning of a benzoyl-CoA:taxane 2alpha-O-benzoyltransferase cDNA from taxus and functional expression in Escherichia coli." Proc Natl Acad Sci U S A 97(25);13591-6. PMID: 11095755
Inoue95: Inoue J, Shaw JP, Rekik M, Harayama S (1995). "Overlapping substrate specificities of benzaldehyde dehydrogenase (the xylC gene product) and 2-hydroxymuconic semialdehyde dehydrogenase (the xylG gene product) encoded by TOL plasmid pWW0 of Pseudomonas putida." J Bacteriol 177(5);1196-201. PMID: 7868591
James98: James KD, Williams PA (1998). "ntn genes determining the early steps in the divergent catabolism of 4-nitrotoluene and toluene in Pseudomonas sp. strain TW3." J Bacteriol 1998;180(8);2043-9. PMID: 9555884
Kim01a: Kim SH, Virmani D, Wake K, MacDonald K, Kronstad JW, Ellis BE (2001). "Cloning and disruption of a phenylalanine ammonia-lyase gene from Ustilago maydis." Curr Genet 40(1);40-8. PMID: 11570515
Vannelli07: Vannelli T, Wei Qi W, Sweigard J, Gatenby AA, Sariaslani FS (2007). "Production of p-hydroxycinnamic acid from glucose in Saccharomyces cerevisiae and Escherichia coli by expression of heterologous genes from plants and fungi." Metab Eng 9(2);142-51. PMID: 17204442
Xiang02: Xiang L, Moore BS (2002). "Inactivation, complementation, and heterologous expression of encP, a novel bacterial phenylalanine ammonia-lyase gene." J Biol Chem 277(36);32505-9. PMID: 12082112
Xue07: Xue Z, McCluskey M, Cantera K, Sariaslani FS, Huang L (2007). "Identification, characterization and functional expression of a tyrosine ammonia-lyase and its mutants from the photosynthetic bacterium Rhodobacter sphaeroides." J Ind Microbiol Biotechnol 34(9);599-604. PMID: 17602252
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