• Crystal structures of escherichia coli uridine phosphorylase in two native and three complexed forms reveal basis of substrate specificity, induced conformational changes and influence of potassium. (expasy.org)
  • In enzymology, an uridine phosphorylase (EC 2.4.2.3) is an enzyme that catalyzes the chemical reaction uridine + phosphate ⇌ {\displaystyle \rightleftharpoons } uracil + alpha-D-ribose 1-phosphate Thus, the two substrates of this enzyme are uridine and phosphate, whereas its two products are uracil and alpha-D-ribose 1-phosphate. (wikipedia.org)
  • The systematic name of this enzyme class is uridine:phosphate alpha-D-ribosyltransferase. (wikipedia.org)
  • Uridine phosphorylase (UP) is a key enzyme in the pyrimidine salvage pathway that catalyses the reversible phosphorolysis of uridine to uracil and ribose 1-phosphate. (rcsb.org)
  • Uridine + phosphate = uracil + alpha-D-ribose 1-phosphate. (cathdb.info)
  • Then, the resulting 5-isobutyryl ribose was converted to ribosyl-1-phosphate and reacted with uracil using several optimized enzymes, including an engineered ribosyl-1-kinase and uridine phosphorylase. (chemistryviews.org)
  • Uridine phosphorylase (UPase) catalyzes the reversible conversion of uridine into uracil and contributes to the antineoplastic activity of 5′-deoxy-5-fluorouridine (5′-DFUR) and homeostasis of uridine levels in plasma and tissues. (aspetjournals.org)
  • Exogenous uridine and cytidine are mostly converted to uracil by uridine phosphorylase and cytidine deaminase in T. foetus prior to incorporation. (tmu.edu.tw)
  • IC50 values did not significantly differ between CU428 and NP1 for the same analog at either room temperature or 37°C. To investigate the mechanism of inhibition, we used two pyrimidine bases (uracil and thymine) and three nucleosides (uridine, thymidine, and 5-methyluridine) to determine whether the inhibitory effects from the pyrimidine analogs were reversible. (bvsalud.org)
  • UPP1 codes for (synthesizes) the enzyme uridine phosphorylase (UP), also known as uridine-uracil phosphoribosyltransferase, which is responsible for the metabolic breakdown of uridine, a process that generates energy-rich metabolites that the cells can use. (acsh.org)
  • Given that glucose availability influences the use of uridine-derived ribose, we hypothesized that a glucose-depleted microenvironment triggers [pancreatic cancer cells] to upregulate UPP1 [the gene that makes an enzyme that breaks down uridine] as a compensatory response. (acsh.org)
  • These hexameric structures confirm the overall structural similarity of UP to E.coli purine nucleoside phosphorylase (PNP) whereby, in the presence of substrate, each displays a closed conformation resulting from a concerted movement that closes the active site cleft. (rcsb.org)
  • 1. Agarwal, R.P. and Parks, R.E. Purine nucleoside phosphorylase from human erythrocytes. (qmul.ac.uk)
  • 2. Friedkin, M. and Kalckar, H. Nucleoside phosphorylases. (qmul.ac.uk)
  • Substrate specificity of E. coli uridine phosphorylase. (cas.cz)
  • Eventually, uridine diphosphate (UDP) and uridine triphosphate (UTP) are produced down the biosynthetic pathway by kinases and dephosphorylation of ATPs. (biologyonline.com)
  • R) The chemical structure of uridine diphosphate, an alternate fuel for pancreatic cancer cells. (acsh.org)
  • Note that uridine diphosphate contains ribose, which is similar to glucose. (acsh.org)
  • UDPG=uridine diphosphate-glucose. (medscape.com)
  • The underlying mechanism(s) have varied in different cancer cell lines, and include increased fluorouracil anabolism to fluorodeoxyuridine monophosphate, further inhibition of thymidylate synthase, stimulation of thymidine and uridine phosphorylase activities, greater DNA damage, and enhanced natural killer cell-mediated lysis of tumour targets. (nebraska.edu)
  • OMP is then decarboxylated by the enzyme OMP decarboxylase to yield uridine monophosphate (UMP). (biologyonline.com)
  • This study demonstrates uridine phosphorylase as a novel target gene of PGC-1α, which induces the transcription and enzymatic activity of UPase in various cancer cells and thus augments their susceptibility to 5′-DFUR. (aspetjournals.org)
  • Preliminary investigation of the three-dimensional structure of Salmonella typhimurium uridine phosphorylase in the crystalline state. (cathdb.info)
  • The synthesis and base pairing properties of platinum complexes based on uridine and deoxyuridine nucleosides and preliminary studies of their antiproliferative activity are described. (bvsalud.org)
  • Platinum(II) uridine and deoxyuridine complexes were synthesized by C-I oxidative addition to Pt(0)(PPh3)4. (bvsalud.org)
  • Inhibiting liver UP in humans raises blood uridine levels and produces a protective effect ("uridine rescue") against the toxicity of the chemotherapeutic agent 5-fluorouracil without reducing its antitumour activity. (rcsb.org)
  • Uridine(5')diphospho(1)-alpha-d-glucose. (ox.ac.uk)
  • Uridine-derived ribose fuels glucose-restricted pancreatic cancer. (acsh.org)
  • Column 1 shows RMA in the absence (minus sign, red circle) of glucose, uridine, and ribose. (acsh.org)
  • Taken together, our results corroborate the regulatory function of PGC-1α in uridine homeostasis and imply its links with the energy metabolism. (aspetjournals.org)
  • It's because cancer cells are perfectly willing to switch to another fuel source - uridine (Figure 1). (acsh.org)
  • 16. Differences in activities and substrate specificity of human and murine pyrimidine nucleoside phosphorylases: implications for chemotherapy with 5-fluoropyrimidines. (nih.gov)
  • UPP1, or uridine phosphorylase 1, is a pyrimidine nucleoside phosphorylase. (nih.gov)
  • Pyrimidine nucleoside phosphorylases can add ribose or deoxyribose to pyrimidine bases to form nucleosides that can be incorporated into RNA or DNA. (nih.gov)
  • In the last 10 years, the scientific interests of I.A. Mikhailopulo focused on studying the mechanism of functioning of nucleoside phosphorylases (NF), the mechanisms of substrate binding and its activation in the catalytic center of these enzymes. (gov.by)
  • Academician Miroshnikov A.I.). One of the most interesting results of this period of work is the establishment of the important role of the serine-90 catalytic center of purine nucleoside phosphorylase (PNP) from E. coli in the binding and activation of a number of substrates. (gov.by)
  • Shows substrate specificity and accept uridine, deoxyuridine, and thymidine as well as the two pyrimidine nucleoside analogs 5-fluorouridine and 5-fluoro-2(')-deoxyuridine as substrates. (nih.gov)
  • Metabolite profiling revealed that uracil accumulates in the livers of these mice due to increased uridine phosphorylase UPP2 activity. (bvsalud.org)
  • Trifluridine (trye flure' i deen)/tipiracil (tye pir' a sil) combines an antineoplastic pyrimidine analogue (2-deoxy-5-trifluoromethyl uridine) with a thymidine phosphorylase inhibitor that blocks its rapid metabolism, thus increasing the bioavailability of trifluridine. (nih.gov)
  • 6. Key role of uridine kinase and uridine phosphorylase in the homeostatic regulation of purine and pyrimidine salvage in brain. (nih.gov)
  • Fluorouridine monophosphate is directly generated from 5FU by the action of orotate phosphoribosyl transferase (OPRT), or is sequentially converted from 5FU by the actions of uridine phosphorylase (UP) and uridine kinase (UK). (medscape.com)
  • Then, the resulting 5-isobutyryl ribose was converted to ribosyl-1-phosphate and reacted with uracil using several optimized enzymes, including an engineered ribosyl-1-kinase and uridine phosphorylase. (chemistryviews.org)
  • The systematic name of this enzyme class is uridine:phosphate alpha-D-ribosyltransferase. (wikipedia.org)
  • UDP-glucose is an R-state inhibitor of glycogen phosphorylase b, competitive with the substrate, glucose 1-phosphate and noncompetitive with the allosteric activator, AMP. (ox.ac.uk)
  • An enzyme that catalyzes the transfer of ribose from uridine to orthophosphate, forming uracil and ribose 1-phosphate. (nih.gov)
  • Uridine(5')diphospho(1)-alpha-D-glucose. (ox.ac.uk)
  • Diffusion of 100 mM UDP-glucose into crystals of phosphorylase b resulted in a difference Fourier synthesis at 0.3-nm resolution that showed two peaks: (a) binding at the allosteric site and (b) binding at the catalytic site. (ox.ac.uk)
  • The pyrophosphate is also well located with the glucose phosphate interacting with the main-chain NH groups at the start of the glycine-loop alpha helix and the uridine phosphate interacting through a water molecule with the 5'-phosphate of the cofactor pyridoxal phosphate and with the side chains of residues Tyr-573, Lys-574 and probably Arg-569. (ox.ac.uk)
  • 9. Uridine Metabolism and Its Role in Glucose, Lipid, and Amino Acid Homeostasis. (nih.gov)
  • 4LNH: Crystal structure of uridine phosphorylase from Vibrio fischeri ES114, NYSGRC Target 29520. (rcsb.org)
  • Several tissue-specific isoforms of phosphorylase are noted. (medscape.com)
  • 10. Abnormalities in uridine homeostatic regulation and pyrimidine nucleotide metabolism as a consequence of the deletion of the uridine phosphorylase gene. (nih.gov)
  • In enzymology, an uridine phosphorylase (EC 2.4.2.3) is an enzyme that catalyzes the chemical reaction uridine + phosphate ⇌ {\displaystyle \rightleftharpoons } uracil + alpha-D-ribose 1-phosphate Thus, the two substrates of this enzyme are uridine and phosphate, whereas its two products are uracil and alpha-D-ribose 1-phosphate. (wikipedia.org)
  • Vitamin D Regulation of the Uridine Phosphorylase 1 Gene and Uridine-Induced DNA Damage in Colon in African Americans and European Americans. (uchicago.edu)
  • Trifluridine triphosphate is metabolized by thymidine phosphorylase which is inhibited by tipiracil, thus providing a longer half-life and increased intracellular concentrations of active phosphorylated trifluridine. (nih.gov)
  • 1. Disruption of uridine homeostasis links liver pyrimidine metabolism to lipid accumulation. (nih.gov)
  • 8. Uridine phosophorylase: an important enzyme in pyrimidine metabolism and fluoropyrimidine activation. (nih.gov)
  • 2. Uridine prevents tamoxifen-induced liver lipid droplet accumulation. (nih.gov)
  • 11. Uridine affects liver protein glycosylation, insulin signaling, and heme biosynthesis. (nih.gov)
  • 13. Uridine prevents fenofibrate-induced fatty liver. (nih.gov)
  • However the position of the uridine cannot be located although analysis by thin-layer chromatography showed that no degradation had taken place. (ox.ac.uk)