Disease relevance of L-dihydroorotate

• Lactococcus lactis dihydroorotate dehydrogenase A mutants reveal important facets of the enzymatic function [1].
• Based on these results and on analysis of published sequences, we propose that the architecture of the deltakappa-enzyme is representative for the dihydroorotate dehydrogenases from Gram-positive bacteria [2].
• The inhibition of dihydro-orotase (E 3.5.2.3) and dihydroorotate (DHO) dehydrogenase (dihydro-orotate oxidase, EC 1.3.3.1) by cellular orotate (OA) in Ehrlich ascites cells was studied by measuring the accumulation of the intermediates of de novo pyrimidine biosynthesis at various times after the addition of 6-azauridine to the culture medium [3].
• Product inhibition showed that the E. coli enzyme, in contrast to the L. lactis enzyme, has separate binding sites for dihydroorotate and the electron acceptor [4].
• Biochemical characterization of the heteromeric Bacillus subtilis dihydroorotate dehydrogenase and its isolated subunits [5].

High impact information on L-dihydroorotate

• The levels of carbamoylphosphate synthase and orotidine 5'-monophosphate decarboxylase are approximately 3-fold enhanced, while the activities of dihydroorotase and dihydroorotate oxidase appear largely unaffected by the mutation [6].
• Our results suggest that brequinar sodium inhibits dihydroorotate dehydrogenase by binding to the enzyme at a unique site that is distinct from the dihydroorotate or the ubiquinone-binding site [7].
• CAD was not concentrated near the mitochondria where the next enzyme of the de novo pathway, dihydroorotate dehydrogenase, is localized, which indicates that the intermediate dihydroorotate is not channeled, but rather dissociates from CAD and diffuses through the bulk cellular fluid [8].
• Lys-D48 is required for charge stabilization, rapid flavin reduction, and internal electron transfer in the catalytic cycle of dihydroorotate dehydrogenase B of Lactococcus lactis [9].
• In addition, there was also a concomitant up-regulation of aspartate transcarbamoylase, however, dihydroorotase and dihydroorotate dehydrogenase are not up-regulated in these cell lines [10].

Chemical compound and disease context of L-dihydroorotate

• The two enzymes represent two distinct evolutionary families of dihydroorotate dehydrogenases, but sedimentation in sucrose gradients suggests a dimeric structure also of the E. coli enzyme [4].
• Recombinant T. cruzi DHOD1 and DHOD2 expressed in E. coli possess similar enzymatic properties, including optimal pH, optimal temperature, Vmax, and Km for dihydroorotate and fumarate [11].
• Activities of the five enzymes specific for the pyrimidine biosynthetic pathway, aspartate carbamoyl-transferase (ACTase), dihydroorotase (DHOase), dihydroorotate dehydrogenase (DHOdehase), orotate phosphoribosyltransferase (OMPppase), and orotidine 5'-phosphate decarboxylase (OMPdecase) were found in cell-free extracts of Neisseria meningitidis [12].

Biological context of L-dihydroorotate

• The pH-rate profiles for the hydrolysis of dihydroorotate or thiodihydroorotate demonstrated that a single group from the enzyme must be unprotonated for maximal catalytic activity [13].
• Active site of dihydroorotate dehydrogenase A from Lactococcus lactis investigated by chemical modification and mutagenesis [14].
• We propose that pyrDII encodes a protein subunit of dihydroorotate dehydrogenase that catalyzes electron transfer from the pyrDI-encoded subunit to components of the electron transport chain [15].
• The deletion mutation was not corrected by a plasmid encoding pyrDI, the previously identified gene encoding dihydroorotate dehydrogenase, but was complemented by a plasmid encoding pyrDII [15].
• Detailed kinetics experiments revealed uncompetitive inhibition with respect to dihydroorotate (Kiu = 0.94 microM) and non-competitive inhibition with respect to decylubiquinone (Kic = 1.09 microM, Kiu = 1.05 microM) [16].

Anatomical context of L-dihydroorotate

• Structural and functional comparison of agents interfering with dihydroorotate, succinate and NADH oxidation of rat liver mitochondria [17].

Associations of L-dihydroorotate with other chemical compounds

• Dihydroorotate dehydrogenase (DHODH) catalyzes the oxidation of dihydroorotate (DHO) to produce orotate, a key step in pyrimidine biosynthesis [18].
• Dihydroorotate dehydrogenase (DHOD) oxidizes dihydroorotate (DHO) to orotate in the only redox reaction of pyrimidine biosynthesis [19].
• METHODS: Urine or urine-soaked filter-paper strips were used to measure N-carbamyl-aspartate, dihydroorotate, orotate, orotidine, uridine, and uracil [20].
• Our detailed kinetic investigations of the bisubstrate reaction catalyzed by rat dihydroorotate dehydrogenase revealed a noncompetitive type of inhibition by A77-1726 with respect to the substrate dihydroorotate and the cosubstrates ubiquinone or decylubiquinone [21].
• Because dihydroorotate, the one-ring open metabolites, and furosemide all have a carboxylate group, it was concluded that a negative charge on the substrate strengthened binding to the positively charged active site [22].

Gene context of L-dihydroorotate

• Nucleotide sequence of the pyrD gene of Escherichia coli and characterization of the flavoprotein dihydroorotate dehydrogenase [23].
• Dihydroorotate (dhout) and orotate (orout) utilizer mutants in yeast: identification of the dhout mutation and allelism of the DHO and URE2 genes [24].
• Efforts to generate mammalian dihydroorotate dehydrogenases with low production costs from bacteria resulted in successful overexpression of the carboxy-terminal-modified rat and human dihydroorotate dehydrogenase in XL-1 Blue cells [25].
• The cDNA, corresponding to the active dihydroorotase domain as isolated after digestion of dihydroorotate synthetase with elastase, has been sub-cloned into the expression vector pCW12 which was then used to transform Escherichia coli S phi 1263 pyrC- lacking dihydroorotase activity [26].
• Dihydroorotate dehydrogenase (DHODH) catalyzes the oxidation of dihydroorotate to orotate in the pyrimidine biosynthesis pathway [27].

Analytical, diagnostic and therapeutic context of L-dihydroorotate

• Thermodynamic basis of electron transfer in dihydroorotate dehydrogenase B from Lactococcus lactis: analysis by potentiometry, EPR spectroscopy, and ENDOR spectroscopy [28].
• In this paper, we report the overproduction, purification, and crystallization of dihydroorotate dehydrogenase A. In solution, the enzyme is bright yellow [29].
• A spectrophotometric detection HPLC assay for dihydroorotate was also developed [22].

References