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: pyrimidine biosynthesis
|Superclasses:||Biosynthesis → Nucleosides and Nucleotides Biosynthesis → Pyrimidine Nucleotide Biosynthesis → Pyrimidine Nucleotides De Novo Biosynthesis → Pyrimidine Ribonucleotides De Novo Biosynthesis|
Pyrimidine and purine nucleoside triphosphates are the activated precursors of DNA and RNA. The pyrimidine deoxyribonucleoside triphosphates dCTP and dTTP are incorporated into DNA while the ribonucleoside triphosphates CTP and UTP are incorporated into RNA. In addition, their diphosphates form activated derivatives of other molecules, such as UDP-α-D-glucose, CMP-3-deoxy-D-manno-octulosonate and dTDP-α-D-fucopyranose, for use in biosynthesis of polysaccharides, glycoproteins and phospholipids [Zhou98, Giermann02, Schroder05, Zrenner06].
In addition to de novo biosynthesis, salvage pathways reutilize exogenous free bases and nucleosides and some of the resulting pyrimidine nucleotides can enter the de novo biosynthesis pathways (see pyrimidine ribonucleosides salvage I, pyrimidine nucleobases salvage I and pyrimidine deoxyribonucleosides salvage). The de novo biosynthetic pathways consume relatively large amounts of high energy phosphate and reducing power, and thus organisms prefer to use salvage pathways when possible. However, the de novo biosynthetic pathways are necessary when exogenous precursors are limiting. In order to conserve resources, the de novo pathways are regulated both by allosteric enzymes and at the gene expression level. These essential, evolutionarily conserved biosynthetic and salvage pathways are found in both prokaryotes and eukaryotes.
The pyrimidine nucleotide de novo biosynthetic pathway derives in part from the central metabolic precursors oxaloacetate and D-ribose 5-phosphate. L-aspartate, a precursor of pyrimidine ribonucleotides, is derived from oxaloacetate, which is generated in the TCA cycle.
About This Pathway
The de novo biosynthesis of UMP appears to be one of the most ancient biochemical pathways as it is evolutionary conserved in all species. The pathway converts hydrogen carbonate, L-glutamine, L-aspartate and 5-phospho-α-D-ribose 1-diphosphate (PRPP) to UMP (UMP), a pyrimidine nucleotide that can be subsequently converted to all other pyrimidine nucleotides.
The penultimate enzyme in this pathway, nucleoside diphosphate kinase (NDK), catalyzes a reaction in which the terminal phosphate of a nucleoside triphosphate is transferred to a nucleoside diphosphate - in this case, the transfer of a phosphate from the purine ATP to the pyrimidine UDP, forming UTP. The enzyme has a broad substrate specificity, and is involved in the biosynthesis of several nucleoside-triphosphates, including formation of CTP from CDP.
Interconversion between thymidine and cytidine nucleotides is possible only at the level of nucleoside triphosphates, by the glutamine (or ammonia)-dependent enzyme CTP synthase.
Unification Links: EcoCyc:PWY0-162
Martha Arnaud on Tue Jan 21, 2003:
This pathway supersedes the pathway formerly called "pyrimidine biosynthesis."
Okada04: Okada K, Ohara K, Yazaki K, Nozaki K, Uchida N, Kawamukai M, Nojiri H, Yamane H (2004). "The AtPPT1 gene encoding 4-hydroxybenzoate polyprenyl diphosphate transferase in ubiquinone biosynthesis is required for embryo development in Arabidopsis thaliana." Plant Mol Biol 55(4);567-77. PMID: 15604701
Aghajari94: Aghajari N, Jensen KF, Gajhede M (1994). "Crystallization and preliminary X-ray diffraction studies on the Apo form of orotate phosphoribosyltransferase from Escherichia coli." J Mol Biol 241(2);292-4. PMID: 8057372
Alam04: Alam N, Stieglitz KA, Caban MD, Gourinath S, Tsuruta H, Kantrowitz ER (2004). "240s loop interactions stabilize the T state of Escherichia coli aspartate transcarbamoylase." J Biol Chem 279(22);23302-10. PMID: 15014067
Anderson75a: Anderson PM, Carlson JD (1975). "Reversible reaction of cyanate with a reactive sulfhydryl group at the glutamine binding site of carbamyl phosphate synthetase." Biochemistry 1975;14(16);3688-94. PMID: 240389
Anderson83: Anderson PM (1983). "CTP synthetase from Escherichia coli: an improved purification procedure and characterization of hysteretic and enzyme concentration effects on kinetic properties." Biochemistry 22(13);3285-92. PMID: 6349684
Arifuzzaman06: Arifuzzaman M, Maeda M, Itoh A, Nishikata K, Takita C, Saito R, Ara T, Nakahigashi K, Huang HC, Hirai A, Tsuzuki K, Nakamura S, Altaf-Ul-Amin M, Oshima T, Baba T, Yamamoto N, Kawamura T, Ioka-Nakamichi T, Kitagawa M, Tomita M, Kanaya S, Wada C, Mori H (2006). "Large-scale identification of protein-protein interaction of Escherichia coli K-12." Genome Res 16(5);686-91. PMID: 16606699
Bearne01: Bearne SL, Hekmat O, Macdonnell JE (2001). "Inhibition of Escherichia coli CTP synthase by glutamate gamma-semialdehyde and the role of the allosteric effector GTP in glutamine hydrolysis." Biochem J 356(Pt 1);223-32. PMID: 11336655
Begley00: Begley TP, Appleby TC, Ealick SE (2000). "The structural basis for the remarkable catalytic proficiency of orotidine 5'-monophosphate decarboxylase." Curr Opin Struct Biol 10(6);711-8. PMID: 11114509
Bennett04: Bennett SE, Chen CY, Mosbaugh DW (2004). "Escherichia coli nucleoside diphosphate kinase does not act as a uracil-processing DNA repair nuclease." Proc Natl Acad Sci U S A 101(17);6391-6. PMID: 15096615
Bjornberg01: Bjornberg O, Jordan DB, Palfey BA, Jensen KF (2001). "Dihydrooxonate is a substrate of dihydroorotate dehydrogenase (DHOD) providing evidence for involvement of cysteine and serine residues in base catalysis." Arch Biochem Biophys 391(2);286-94. PMID: 11437361
Bjornberg99: Bjornberg O, Gruner AC, Roepstorff P, Jensen KF (1999). "The activity of Escherichia coli dihydroorotate dehydrogenase is dependent on a conserved loop identified by sequence homology, mutagenesis, and limited proteolysis." Biochemistry 38(10);2899-908. PMID: 10074342
Bonekamp84: Bonekamp F, Clemmesen K, Karlstrom O, Jensen KF (1984). "Mechanism of UTP-modulated attenuation at the pyrE gene of Escherichia coli: an example of operon polarity control through the coupling of translation to transcription." EMBO J 3(12);2857-61. PMID: 6098450
Bonekamp85: Bonekamp F, Andersen HD, Christensen T, Jensen KF (1985). "Codon-defined ribosomal pausing in Escherichia coli detected by using the pyrE attenuator to probe the coupling between transcription and translation." Nucleic Acids Res 13(11);4113-23. PMID: 2989788
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