Amidotransferase and Phosphoribosylpyrophosphate
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Nucleotide Degradation
Nucleotide Degradation Nucleotide Degradation The Digestion Pathway • Ingestion of food always includes nucleic acids. • As you know from BI 421, the low pH of the stomach does not affect the polymer. • In the duodenum, zymogens are converted to nucleases and the nucleotides are converted to nucleosides by non-specific phosphatases or nucleotidases. nucleases • Only the non-ionic nucleosides are taken & phospho- diesterases up in the villi of the small intestine. Duodenum Non-specific phosphatases • In the cell, the first step is the release of nucleosides) the ribose sugar, most effectively done by a non-specific nucleoside phosphorylase to give ribose 1-phosphate (Rib1P) and the free bases. • Most ingested nucleic acids are degraded to Rib1P, purines, and pyrimidines. 1 Nucleotide Degradation: Overview Fate of Nucleic Acids: Once broken down to the nitrogenous bases they are either: Nucleotides 1. Salvaged for recycling into new nucleic acids (most cells; from internal, Pi not ingested, nucleic Nucleosides acids). Purine Nucleoside Pi aD-Rib 1-P (or Rib) 2. Oxidized (primarily in the Phosphorylase & intestine and liver) by first aD-dRib 1-P (or dRib) converting to nucleosides, Bases then to –Uric Acid (purines) –Acetyl-CoA & Purine & Pyrimidine Oxidation succinyl-CoA Salvage Pathway (pyrimidines) The Salvage Pathways are in competition with the de novo biosynthetic pathways, and are both ANABOLISM Nucleotide Degradation Catabolism of Purines Nucleotides: Nucleosides: Bases: 1. Dephosphorylation (via 5’-nucleotidase) 2. Deamination and hydrolysis of ribose lead to production of xanthine. 3. Hypoxanthine and xanthine are then oxidized into uric acid by xanthine oxidase. Spiders and other arachnids lack xanthine oxidase. -
35 Disorders of Purine and Pyrimidine Metabolism
35 Disorders of Purine and Pyrimidine Metabolism Georges van den Berghe, M.- Françoise Vincent, Sandrine Marie 35.1 Inborn Errors of Purine Metabolism – 435 35.1.1 Phosphoribosyl Pyrophosphate Synthetase Superactivity – 435 35.1.2 Adenylosuccinase Deficiency – 436 35.1.3 AICA-Ribosiduria – 437 35.1.4 Muscle AMP Deaminase Deficiency – 437 35.1.5 Adenosine Deaminase Deficiency – 438 35.1.6 Adenosine Deaminase Superactivity – 439 35.1.7 Purine Nucleoside Phosphorylase Deficiency – 440 35.1.8 Xanthine Oxidase Deficiency – 440 35.1.9 Hypoxanthine-Guanine Phosphoribosyltransferase Deficiency – 441 35.1.10 Adenine Phosphoribosyltransferase Deficiency – 442 35.1.11 Deoxyguanosine Kinase Deficiency – 442 35.2 Inborn Errors of Pyrimidine Metabolism – 445 35.2.1 UMP Synthase Deficiency (Hereditary Orotic Aciduria) – 445 35.2.2 Dihydropyrimidine Dehydrogenase Deficiency – 445 35.2.3 Dihydropyrimidinase Deficiency – 446 35.2.4 Ureidopropionase Deficiency – 446 35.2.5 Pyrimidine 5’-Nucleotidase Deficiency – 446 35.2.6 Cytosolic 5’-Nucleotidase Superactivity – 447 35.2.7 Thymidine Phosphorylase Deficiency – 447 35.2.8 Thymidine Kinase Deficiency – 447 References – 447 434 Chapter 35 · Disorders of Purine and Pyrimidine Metabolism Purine Metabolism Purine nucleotides are essential cellular constituents 4 The catabolic pathway starts from GMP, IMP and which intervene in energy transfer, metabolic regula- AMP, and produces uric acid, a poorly soluble tion, and synthesis of DNA and RNA. Purine metabo- compound, which tends to crystallize once its lism can be divided into three pathways: plasma concentration surpasses 6.5–7 mg/dl (0.38– 4 The biosynthetic pathway, often termed de novo, 0.47 mmol/l). starts with the formation of phosphoribosyl pyro- 4 The salvage pathway utilizes the purine bases, gua- phosphate (PRPP) and leads to the synthesis of nine, hypoxanthine and adenine, which are pro- inosine monophosphate (IMP). -
Purine Metabolism in Cultured Endothelial Cells
PURINE METABOLISM IN MAN-III Biochemical, Immunological, and Cancer Research Edited by Aurelio Rapado Fundacion Jimenez Diaz Madrid, Spain R.W.E. Watts M.R.C. Clinical Research Centre Harrow, England and Chris H.M.M. De Bruyn Department of Human Genetics University of Nijmegen Faculty of Medicine Nijmegen, The Netherlands PLENUM PRESS · NEW YORK AND LONDON Contents of Part Β I. PURINE METABOLISM PATHWAYS AND REGULATION A. De Novo Synthesis; Precursors and Regulation De Novo Purine Synthesis in Cultured Human Fibroblasts 1 R.B. Gordon, L. Thompson, L.A. Johnson, and B.T. Emmerson Comparative Metabolism of a New Antileishmanial Agent, Allopurinol Riboside, in the Parasite and the Host Cell 7 D. J. Nelson, S.W. LaFon, G.B. Elion, J.J. Marr, and R.L. Berens Purine Metabolism in Rat Skeletal Muscle 13 E. R. Tully and T.G. Sheehan Alterations in Purine Metabolism in Cultured Fibroblasts with HGPRT Deficiency and with PRPPP Synthetase Superactivity 19 E. Zoref-Shani and 0. Sperling Purine Metabolism in Cultured Endothelial Cells 25 S. Nees, A.L. Gerbes, B. Willershausen-Zönnchen, and E. Gerlach Determinants of 5-Phosphoribosyl-l-Pyrophosphate (PRPP) Synthesis in Human Fibroblasts 31 K.0, Raivio, Ch. Lazar, H. Krumholz, and M.A. Becker Xanthine Oxidoreductase Inhibition by NADH as a Regulatory Factor of Purine Metabolism 35 M.M. Jezewska and Z.W. Kaminski vii viii CONTENTS OF PART Β Β. Nucleotide Metabolism Human Placental Adenosine Kinase: Purification and Characterization 41 CM. Andres, T.D. Palella, and I.H. Fox Long-Term Effects of Ribose on Adenine Nucleotide Metabolism in Isoproterenol-Stimulated Hearts . -
Nucleotide Metabolism
NUCLEOTIDE METABOLISM General Overview • Structure of Nucleotides Pentoses Purines and Pyrimidines Nucleosides Nucleotides • De Novo Purine Nucleotide Synthesis PRPP synthesis 5-Phosphoribosylamine synthesis IMP synthesis Inhibitors of purine synthesis Synthesis of AMP and GMP from IMP Synthesis of NDP and NTP from NMP • Salvage pathways for purines • Degradation of purine nucleotides • Pyrimidine synthesis Carbamoyl phosphate synthesisOrotik asit sentezi • Pirimidin nükleotitlerinin yıkımı • Ribonükleotitlerin deoksiribonükleotitlere dönüşümü Basic functions of nucleotides • They are precursors of DNA and RNA. • They are the sources of activated intermediates in lipid and protein synthesis (UDP-glucose→glycogen, S-adenosylmathionine as methyl donor) • They are structural components of coenzymes (NAD(P)+, FAD, and CoA). • They act as second messengers (cAMP, cGMP). • They play important role in carrying energy (ATP, etc). • They play regulatory roles in various pathways by activating or inhibiting key enzymes. Structures of Nucleotides • Nucleotides are composed of 1) A pentose monosaccharide (ribose or deoxyribose) 2) A nitrogenous base (purine or pyrimidine) 3) One, two or three phosphate groups. Pentoses 1.Ribose 2.Deoxyribose •Deoxyribonucleotides contain deoxyribose, while ribonucleotides contain ribose. •Ribose is produced in the pentose phosphate pathway. Ribonucleotide reductase converts ribonucleoside diphosphate deoxyribonucleotide. Nucleotide structure-Base 1.Purine 2.Pyrimidine •Adenine and guanine, which take part in the structure -
Effects of Allopurinol and Oxipurinol on Purine Synthesis in Cultured Human Cells
Effects of allopurinol and oxipurinol on purine synthesis in cultured human cells William N. Kelley, James B. Wyngaarden J Clin Invest. 1970;49(3):602-609. https://doi.org/10.1172/JCI106271. Research Article In the present study we have examined the effects of allopurinol and oxipurinol on thed e novo synthesis of purines in cultured human fibroblasts. Allopurinol inhibits de novo purine synthesis in the absence of xanthine oxidase. Inhibition at lower concentrations of the drug requires the presence of hypoxanthine-guanine phosphoribosyltransferase as it does in vivo. Although this suggests that the inhibitory effect of allopurinol at least at the lower concentrations tested is a consequence of its conversion to the ribonucleotide form in human cells, the nucleotide derivative could not be demonstrated. Several possible indirect consequences of such a conversion were also sought. There was no evidence that allopurinol was further utilized in the synthesis of nucleic acids in these cultured human cells and no effect of either allopurinol or oxipurinol on the long-term survival of human cells in vitro could be demonstrated. At higher concentrations, both allopurinol and oxipurinol inhibit the early steps ofd e novo purine synthesis in the absence of either xanthine oxidase or hypoxanthine-guanine phosphoribosyltransferase. This indicates that at higher drug concentrations, inhibition is occurring by some mechanism other than those previously postulated. Find the latest version: https://jci.me/106271/pdf Effects of Allopurinol and Oxipurinol on Purine Synthesis in Cultured Human Cells WILLIAM N. KELLEY and JAMES B. WYNGAARDEN From the Division of Metabolic and Genetic Diseases, Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina 27706 A B S TR A C T In the present study we have examined the de novo synthesis of purines in many patients. -
Metabolomics Identifies Pyrimidine Starvation As the Mechanism of 5-Aminoimidazole-4-Carboxamide-1- Β-Riboside-Induced Apoptosis in Multiple Myeloma Cells
Published OnlineFirst April 12, 2013; DOI: 10.1158/1535-7163.MCT-12-1042 Molecular Cancer Cancer Therapeutics Insights Therapeutics Metabolomics Identifies Pyrimidine Starvation as the Mechanism of 5-Aminoimidazole-4-Carboxamide-1- b-Riboside-Induced Apoptosis in Multiple Myeloma Cells Carolyne Bardeleben1, Sanjai Sharma1, Joseph R. Reeve3, Sara Bassilian3, Patrick Frost1, Bao Hoang1, Yijiang Shi1, and Alan Lichtenstein1,2 Abstract To investigate the mechanism by which 5-aminoimidazole-4-carboxamide-1-b-riboside (AICAr) induces apoptosis in multiple myeloma cells, we conducted an unbiased metabolomics screen. AICAr had selective effects on nucleotide metabolism, resulting in an increase in purine metabolites and a decrease in pyrimidine metabolites. The most striking abnormality was a 26-fold increase in orotate associated with a decrease in uridine monophosphate (UMP) levels, indicating an inhibition of UMP synthetase (UMPS), the last enzyme in the de novo pyrimidine biosynthetic pathway, which produces UMP from orotate and 5-phosphoribosyl- a-pyrophosphate (PRPP). As all pyrimidine nucleotides can be synthesized from UMP, this suggested that the decrease in UMP would lead to pyrimidine starvation as a possible cause of AICAr-induced apoptosis. Exogenous pyrimidines uridine, cytidine, and thymidine, but not purines adenosine or guanosine, rescued multiple myeloma cells from AICAr-induced apoptosis, supporting this notion. In contrast, exogenous uridine had no protective effect on apoptosis resulting from bortezomib, melphalan, or metformin. Rescue resulting from thymidine add-back indicated apoptosis was induced by limiting DNA synthesis rather than RNA synthesis. DNA replicative stress was identified by associated H2A.X phosphorylation in AICAr-treated cells, which was also prevented by uridine add-back. -
Xanthine Oxidase Assay (XO) Cat
Xanthine Oxidase Assay (XO) Cat. No. 8458 100 Tests in 96-well plate Introduction Xanthine Oxidase (XO) located predominantly in the liver and intestine in mammalian tissues and catalyzes the hydroxylation of hypoxanthine to xanthine and then to uric acid and hydrogen peroxide. XO activity is normally very low in blood and liver injury can result in the release of XO into blood. XO activity or expression can be up-regulated in gout and cardiovascular disease. This colorimetric assay is based on XO-catalyzed oxidation of xanthine, in which the formed hydrogen peroxide is catalyzed by peroxidase and reacts with 4-aminoantipyrine to form the product dye. The color intensity of the reaction product at 550nm is directly proportional to XO activity in the sample. Kit Components Cat. No. # of vials Reagent Quantity Storage 8458a 1 Assay buffer 10 mL 4°C 8458b 1 Xanthine Oxidase standard 0.2 mL -20°C 8458c 1 Xanthine 2.0 mL -20°C 8458d 1 Substrate mix 1.6 mL -20°C 8458e 1 Enzyme mix 0.1 mL -20°C Product Use The Xanthine Oxidase Assay kit measures the xanthine oxidase level of different types of samples, such as serum, plasma, tissues. This product is for research purposes only and not for use in animals, humans, or diagnostic procedures. Quality Control Serially diluted xanthine oxidase solutions with concentrations ranging from 7.81 to 125 mU/mL are measured with the ScienCell™ Xanthine Oxidase Assay kit. The increase in OD550nm is monitored as a function of time (Figure 1) and the resulting standard curve of ∆OD550nm/min vs xanthine oxidase activity are plotted (Figure 2). -
Xanthine Oxidoreductase in Cancer
Cancer Medicine Open Access REVIEW Xanthine oxidoreductase in cancer: more than a differentiation marker Maria Giulia Battelli, Letizia Polito, Massimo Bortolotti & Andrea Bolognesi Department of Experimental, Diagnostic and Specialty Medicine – DIMES, Alma Mater Studiorum – University of Bologna, General Pathology Unit, Via S. Giacomo 14, 40126 Bologna, Italy Keywords Abstract Differentiation, oncogenesis, reactive oxygen and nitrogen species, uric acid, xanthine Human xanthine oxidoreductase (XOR) catalyzes the last two steps of purine oxidoreductase catabolism and is present in two interconvertible forms, which may utilize O2 or NAD+ as electron acceptors. In addition to uric acid, XOR products may Correspondence comprise reactive oxygen and nitrogen species that have many biologic effects, Letizia Polito, Department of Experimental, including inflammation, endothelial dysfunction, and cytotoxicity, as well as Diagnostic and Specialty Medicine – DIMES, mutagenesis and induction of proliferation. XOR is strictly modulated at the Alma Mater Studiorum – University of Bologna, General Pathology Unit, Via S. transcriptional and post-translational levels, and its expression and activity are Giacomo 14, 40126 Bologna, Italy. highly variable in cancer. Xanthine oxidoreductase (XOR) expression has been Tel: +39 051 2094700; Fax: +39 051 2094746; negatively associated with a high malignity grade and a worse prognosis in E-mail: [email protected] neoplasms of the breast, liver, gastrointestinal tract, and kidney, which normally express a high level of XOR protein. However, the level of XOR expression Funding Information may be associated with a worse outcome in cancer of low XOR-expressing cells, This work was supported by the Pallotti in relation to the inflammatory response elicited through the tissue damage Legacies for Cancer Research. -
Purine and Pyrimidine Biosynthesis
Biosynthesis of Purine & Pyrimidi ne Introduction Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined together to form macromolecules. This process often consists of metabolic pathways. The purines are built upon a pre-existing ribose 5- phosphate. Liver is the major site for purine nucleotide synthesis. Erythrocytes, polymorphonuclear leukocytes & brain cannot produce purines. Pathways • There are Two pathways for the synthesis of nucleotides: 1. De-novo synthesis: Biochemical pathway where nucleotides are synthesized from new simple precursor molecules 2. Salvage pathway: Used to recover bases and nucleotides formed during the degradation of RNA and DNA. Step involved in purine biosynthesis (Adenine & Guanine) • Ribose-5-phosphate, of carbohydrate metabolism is the starting material for purine nucleotide synthesis. • It reacts with ATP to form phosphoribosyl pyrophosphate (PRPP). • Glutamine transfers its amide nitrogen to PRPP to replace pyrophosphate & produce 5- phosphoribosylamine. Catalysed by PRPP glutamyl amidotransferase. • This reaction is the committed. • Phosphoribosylamine reacts with glycine in the presence of ATP to form glycinamide ribosyl 5- phosphate or glycinamide ribotide (GAR).Catalyzed by synthetase. • N10-Formyl tetrahydrofolate donates the formyl group & the product formed is formylglycinamide ribosyl 5-phosphate. Catalyzed by formyltransferase. • Glutamine transfers the second amido amino group to produce formylglycinamidine ribosyl 5- phosphate. Catalyzed by synthetase. • The imidazole ring of the purine is closed in an ATP dependent reaction to yield 5- aminoimidazole ribosyl 5-phosphate. Catalyzed by synthetase. • Incorporation of CO2 (carboxylation) occurs to yield aminoimidazole carboxylate ribosyl 5- phosphate. -
TITLE Adenylate Kinase 2 Deficiency Causes NAD+ Depletion and Impaired Purine Metabolism During Myelopoiesis
bioRxiv preprint doi: https://doi.org/10.1101/2021.07.05.450633; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. TITLE Adenylate Kinase 2 deficiency causes NAD+ depletion and impaired purine metabolism during myelopoiesis AUTHORS Wenqing Wang1, Andew DeVilbiss2, Martin Arreola1, Thomas Mathews2, Misty Martin-Sandoval2, Zhiyu Zhao2, Avni Awani1, Daniel Dever1, Waleed Al-Herz3, Luigi Noratangelo4, Matthew H. Porteus1, Sean J. Morrison2, Katja G. Weinacht1, * 1. Department of Pediatrics, Stanford University School of Medicine, Stanford, California 94305 USA 2. Children’s Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390 USA 3. Department of Pediatrics, Faculty of Medicine, Kuwait University, Safat, 13110 Kuwait 4. Laboratory of Clinical Immunology and Microbiology, National Institute of Health, BETHESDA MD 20814 USA * Corresponding author ABSTRACT Reticular Dysgenesis is a particularly grave from of severe combined immunodeficiency (SCID) that presents with severe congenital neutropenia and a maturation arrest of most cells of the lymphoid lineage. The disease is caused by biallelic loss of function mutations in the mitochondrial enzyme Adenylate Kinase 2 (AK2). AK2 mediates the phosphorylation of adenosine monophosphate (AMP) to adenosine diphosphate (ADP) as substrate for adenosine triphosphate (ATP) synthesis in the mitochondria. Accordingly, it has long been hypothesized that a decline in OXPHOS metabolism is the driver of the disease. The mechanistic basis for Reticular Dysgenesis, however, remained incompletely understood, largely due to lack of appropriate model systems to phenocopy the human disease. -
Monitoring the Redox Status in Multiple Sclerosis
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 31 July 2020 doi:10.20944/preprints202007.0737.v1 Review Monitoring the Redox Status in Multiple Sclerosis Masaru Tanaka 1,2 and László Vécsei 1,2,* 1 MTA-SZTE, Neuroscience Research Group, Semmelweis u. 6, Szeged, H-6725 Hungary; [email protected] 2 Department of Neurology, Interdisciplinary Excellence Centre, Faculty of Medicine, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary * Correspondence: [email protected]; Tel.: +36-62-545-351 Received: date; Accepted: date; Published: date Abstract: Worldwide, over 2.2 million people are suffered from multiple sclerosis (MS), a multifactorial demyelinating disease of the central nervous system, characterized by multifocal inflammatory or demyelinating attacks associated with neuroinflammation and neurodegeneration. The blood, cerebrospinal fluid, and postmortem brain samples of MS patients evidenced the presence of reduction-oxidation (redox) homeostasis disturbance such as the alternations of oxidative and antioxidative enzyme activities and the presence of degradation products. This review article discussed the components of redox homeostasis including reactive chemical species, oxidative enzymes, antioxidative enzymes, and degradation products. The reactive chemical species covered frequently discussed reactive oxygen/nitrogen species, rarely featured reactive chemicals such as sulfur, carbonyls, halogens, selenium, and nucleophilic species that potentially act as reductive as well as pro-oxidative stressors. The antioxidative enzyme systems covered the nuclear factor erythroid-2-related factor 2 (NRF2)-Kelch-like ECH-associated protein 1 (KEAP1) signaling pathway, a possible biomarker sensitive to the initial phase of oxidative stress. Altered components of the redox homeostasis in MS were discussed, some of which turned to be MS subtype- or treatment-specific and thus potentially become diagnostic, prognostic, predictive, and/or therapeutic biomarkers. -
Induced Alterations in the Urine Metabolome in Cardiac Surgery
www.nature.com/scientificreports OPEN Bretschneider solution- induced alterations in the urine metabolome in cardiac surgery Received: 16 August 2018 Accepted: 1 November 2018 patients Published: xx xx xxxx Cheng-Chia Lee1,3, Ya-Ju Hsieh 2, Shao-Wei Chen3,4, Shu-Hsuan Fu2, Chia-Wei Hsu 2, Chih-Ching Wu 2,5,6, Wei Han7, Yunong Li7, Tao Huan7, Yu-Sun Chang2,6,8, Jau-Song Yu2,9,10, Liang Li7, Chih-Hsiang Chang1,3 & Yi-Ting Chen 1,2,11,12 The development of Bretschneider’s histidine-tryptophan-ketoglutarate (HTK) cardioplegia solution represented a major advancement in cardiac surgery, ofering signifcant myocardial protection. However, metabolic changes induced by this additive in the whole body have not been systematically investigated. Using an untargeted mass spectrometry-based method to deeply explore the urine metabolome, we sought to provide a holistic and systematic view of metabolic perturbations occurred in patients receiving HTK. Prospective urine samples were collected from 100 patients who had undergone cardiac surgery, and metabolomic changes were profled using a high-performance chemical isotope labeling liquid chromatography-mass spectrometry (LC-MS) method. A total of 14,642 peak pairs or metabolites were quantifed using diferential 13C-/12C-dansyl labeling LC-MS, which targets the amine/phenol submetabolome from urine specimens. We identifed 223 metabolites that showed signifcant concentration change (fold change > 5) and assembled several potential metabolic pathway maps derived from these dysregulated metabolites. Our data indicated upregulated histidine metabolism with subsequently increased glutamine/glutamate metabolism, altered purine and pyrimidine metabolism, and enhanced vitamin B6 metabolism in patients receiving HTK.