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Tabucchi A, Leoncini R, Pagani R, Pizzichini M, Terzuoli L, Vannoni D, Porcelli B, Marinello E, Dispensa E. Some Aspects of Purine Nucleotide Metabolism in Lymphocytes of B-CLL. TUMORI JOURNAL 2018; 77:112-7. [PMID: 2048222 DOI: 10.1177/030089169107700204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The authors studied the behavior of some enzymes involved in purine nucleotide metabolism in human peripheral blood lymphocytes from normal and B-cell chronic lymphocytic leukemia subjects. Determinations were made with radiochemical methods associated with high performance liquid chromatography. Results indicated a marked increase in de novo purine synthesis enzymes, particularly those of the « inosinic branch point ». The latter were absent in normal lymphocytes, whereas they were well evident in leukemic lymphocytes, with the exception of AMP-S synthetase. Whereas the enzymes of the « salvage pathway » were spared in comparison to other proteins, those of the « catabolic pathway » significantly decreased. The authors discuss the possibility that such enzymes may be used as tumor markers.
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Affiliation(s)
- A Tabucchi
- Istituto di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università di Siena Italy
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2
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Jimmerson LC, Clayton CW, MaWhinney S, Meissner EG, Sims Z, Kottilil S, Kiser JJ. Effects of ribavirin/sofosbuvir treatment and ITPA phenotype on endogenous purines. Antiviral Res 2017; 138:79-85. [PMID: 27956135 PMCID: PMC10837792 DOI: 10.1016/j.antiviral.2016.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/23/2016] [Accepted: 12/03/2016] [Indexed: 12/15/2022]
Abstract
Ribavirin (RBV), a purine analog, causes hemolytic anemia in some patients. In vitro, anemia appears to result from depletion of endogenous purines, but there are limited data in vivo. Single nucleotide polymorphisms in the gene encoding the inosine triphosphatase (ITPA) enzyme have been associated with protection against RBV-induced anemia and may mediate the effect of RBV treatment on endogenous purines. The purpose of this work was to determine the effect of RBV treatment on endogenous purine concentrations in individuals being treated for chronic hepatitis C virus (HCV) infection. Adenosine triphosphate (ATP), guanosine triphosphate (GTP), inosine triphosphate (ITP) and ribavirin triphosphate (RTP) were measured in whole blood obtained from 47 HCV-infected individuals at day zero (baseline), day three, day 28 and day 84 of RBV/sofosbuvir (SOF) treatment. ATP decreased -35.1% and -38.6% (p < 0.0001) at day 28 and day 84 of treatment, respectively compared to baseline. The decrease in ATP was greater in patients with ≤60% ITPA activity compared to those with 100% ITPA activity (-29.4% vs. -9.6%). GTP did not change during treatment but was 16.5% (p = 0.01) higher per 100 pmol/106 cells RTP in those with 100% ITPA activity. No significant change or effect of RTP or ITPA phenotype was noted for ITP. In summary, only ATP was reduced by RBV/SOF treatment and ITPA variants had larger reductions in ATP suggesting RBV-induced anemia is due to a different mechanism than predicted from in-vitro studies. These data emphasize the importance of characterizing the effect of nucleos(t)ide analog treatment on endogenous purines in-vivo.
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Affiliation(s)
- Leah C Jimmerson
- University of Colorado, Skaggs School of Pharmacy and Pharmaceutical Sciences Aurora, CO, USA
| | | | | | - Eric G Meissner
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Zayani Sims
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Shyamasundaran Kottilil
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer J Kiser
- University of Colorado, Skaggs School of Pharmacy and Pharmaceutical Sciences Aurora, CO, USA.
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3
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López-Cruz RI, Crocker DE, Gaxiola-Robles R, Bernal JA, Real-Valle RA, Lugo-Lugo O, Zenteno-Savín T. Plasma Hypoxanthine-Guanine Phosphoribosyl Transferase Activity in Bottlenose Dolphins Contributes to Avoiding Accumulation of Non-recyclable Purines. Front Physiol 2016; 7:213. [PMID: 27375492 PMCID: PMC4898134 DOI: 10.3389/fphys.2016.00213] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/23/2016] [Indexed: 02/04/2023] Open
Abstract
Marine mammals are exposed to ischemia/reperfusion and hypoxia/reoxygenation during diving. During oxygen deprivation, adenosine triphosphate (ATP) breakdown implies purine metabolite accumulation, which in humans is associated with pathological conditions. Purine recycling in seals increases in response to prolonged fasting and ischemia. Concentrations of metabolites and activities of key enzymes in purine metabolism were examined in plasma and red blood cells from bottlenose dolphins (Tursiops truncatus) and humans. Hypoxanthine and inosine monophosphate concentrations were higher in plasma from dolphins than humans. Plasma hypoxanthine-guanine phosphoribosyl transferase (HGPRT) activity in dolphins suggests an elevated purine recycling rate, and a mechanism for avoiding accumulation of non-recyclable purines (xanthine and uric acid). Red blood cell concentrations of hypoxanthine, adenosine diphosphate, ATP and guanosine triphosphate were lower in dolphins than in humans; adenosine monophosphate and nicotinamide adenine dinucleotide concentrations were higher in dolphins. HGPRT activity in red blood cells was higher in humans than in dolphins. The lower concentrations of purine catabolism and recycling by-products in plasma from dolphins could be beneficial in providing substrates for recovery of ATP depleted during diving or vigorous swimming. These results suggest that purine salvage in dolphins could be a mechanism for delivering nucleotide precursors to tissues with high ATP and guanosine triphosphate requirements.
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Affiliation(s)
- Roberto I. López-Cruz
- Programa de Planeación Ambiental y Conservación, Laboratorio de Estrés Oxidativo, Centro de Investigaciones Biológicas del Noroeste, S.C.La Paz, México
| | | | - Ramón Gaxiola-Robles
- Programa de Planeación Ambiental y Conservación, Laboratorio de Estrés Oxidativo, Centro de Investigaciones Biológicas del Noroeste, S.C.La Paz, México
- Instituto Mexicano del Seguro Social, Hospital General de Zona No. 1La Paz, México
| | | | | | - Orlando Lugo-Lugo
- Programa de Planeación Ambiental y Conservación, Laboratorio de Estrés Oxidativo, Centro de Investigaciones Biológicas del Noroeste, S.C.La Paz, México
| | - Tania Zenteno-Savín
- Programa de Planeación Ambiental y Conservación, Laboratorio de Estrés Oxidativo, Centro de Investigaciones Biológicas del Noroeste, S.C.La Paz, México
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4
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Roback JD, Josephson CD, Waller EK, Newman JL, Karatela S, Uppal K, Jones DP, Zimring JC, Dumont LJ. Metabolomics of ADSOL (AS-1) red blood cell storage. Transfus Med Rev 2014; 28:41-55. [PMID: 24636780 DOI: 10.1016/j.tmrv.2014.01.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 01/29/2014] [Accepted: 01/29/2014] [Indexed: 01/13/2023]
Abstract
Population-based investigations suggest that red blood cells (RBCs) are therapeutically effective when collected, processed, and stored for up to 42 days under validated conditions before transfusion. However, some retrospective clinical studies have shown worse patient outcomes when transfused RBCs have been stored for the longest times. Furthermore, studies of RBC persistence in the circulation after transfusion have suggested that considerable donor-to-donor variability exists and may affect transfusion efficacy. To understand the limitations of current blood storage technologies and to develop approaches to improve RBC storage and transfusion efficacy, we investigated the global metabolic alterations that occur when RBCs are stored in AS-1 (AS1-RBC). Leukoreduced AS1-RBC units prepared from 9 volunteer research donors (12 total donated units) were serially sampled for metabolomics analysis over 42 days of refrigerated storage. Samples were tested by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry, and specific biochemical compounds were identified by comparison to a library of purified standards. Over 3 experiments, 185 to 264 defined metabolites were quantified in stored RBC samples. Kinetic changes in these biochemicals confirmed known alterations in glycolysis and other pathways previously identified in RBCs stored in saline, adenine, glucose and mannitol solution (SAGM-RBC). Furthermore, we identified additional alterations not previously seen in SAGM-RBCs (eg, stable pentose phosphate pathway flux, progressive decreases in oxidized glutathione), and we delineated changes occurring in other metabolic pathways not previously studied (eg, S-adenosyl methionine cycle). These data are presented in the context of a detailed comparison with previous studies of SAGM-RBCs from human donors and murine AS1-RBCs. Global metabolic profiling of AS1-RBCs revealed a number of biochemical alterations in stored blood that may affect RBC viability during storage as well as therapeutic effectiveness of stored RBCs in transfusion recipients. These results provide future opportunities to more clearly pinpoint the metabolic defects during RBC storage, to identify biomarkers for donor screening and prerelease RBC testing, and to develop improved RBC storage solutions and methodologies.
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Affiliation(s)
- John D Roback
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA.
| | - Cassandra D Josephson
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Edmund K Waller
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA
| | - James L Newman
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Sulaiman Karatela
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Karan Uppal
- Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Dean P Jones
- Department of Medicine, Emory University School of Medicine, Atlanta, GA
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Liu XZ, Xie D, Yuan HJ, de Brouwer APM, Christodoulou J, Yan D. Hearing loss and PRPS1 mutations: Wide spectrum of phenotypes and potential therapy. Int J Audiol 2012. [PMID: 23190330 DOI: 10.3109/14992027.2012.736032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this review was to evaluate the current literature on phosphoribosylpyrophosphate synthetase 1 (PRPS1)-related diseases and their consequences on hearing function. DESIGN A literature search of peer-reviewed, published journal articles was conducted in online bibliographic databases. STUDY SAMPLE Three databases for medical research were included in this review. RESULTS Mutations in PRPS1 are associated with a spectrum of non-syndromic to syndromic hearing loss. Hearing loss in male patients with PRPS1 mutations is bilateral, moderate to profound, and can be prelingual or postlingual, progressive or non-progressive. Audiogram shapes associated with PRPS1 deafness are usually residual and flat. Female carriers can have unilateral or bilateral hearing impairment. Gain of function mutations in PRPS1 cause a superactivity of the PRS-I protein whereas the loss-of-function mutations result in X-linked nonsyndromic sensorineural deafness type 2 (DFN2), or in syndromic deafness including Arts syndrome and X-linked Charcot-Marie-Tooth disease-5 (CMTX5). CONCLUSIONS Lower residual activity in PRS-I leads to a more severe clinical manifestation. Clinical and molecular findings suggest that the four PRPS1 disorders discovered to date belong to the same disease spectrum. Dietary supplementation with S-adenosylmethionine (SAM) appeared to alleviate the symptoms of Arts syndrome patients, suggesting that SAM could compensate for PRS-I deficiency.
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Affiliation(s)
- Xue Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
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6
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Micheli V, Sestini S. Inborn errors of purine and pyrimidine metabolism: how much we owe to H. Anne Simmonds. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2012; 30:1233-42. [PMID: 22132980 DOI: 10.1080/15257770.2011.608397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
Purines and pyrimidines, regarded for a long time merely as building blocks for nucleic acid synthesis and intermediates in the transfer of metabolic energy, have attracted increasing attention after genetically determined aberrations in their metabolism were linked to a range of symptoms from hyperuricemia and immunodeficiency to neurological disorders. The pathogenesis of such disorders involves cell or mitochondrial damage, but the molecular mechanisms underlying symptoms is often unclear. H. Anne Simmonds made major contributions to the metabolic, clinical, and molecular aspects of these disorders and the Purine Research Laboratory, which she established in London, became the world center for clinical and experimental studies in the field. We owe her gratitude not only for this direct contribution but also for her enthusiasm for purine and pyrimidine research that she transmitted to generations of scientists. Our research in this field stemmed from expertise in pyridine metabolism and its connection with purines, and from clinical involvement with biochemical diagnosis of enzyme deficiencies. We joined H. Anne Simmonds in studying the biochemical basis of altered NAD content in erythrocytes of PNP- and HPRT-deficient patients, discovering some alterations in NAD synthesis and breakdown.
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Affiliation(s)
- Vanna Micheli
- Dipartimento di Biotecnologie, Università di Siena, Siena, Italia.
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7
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Mehrotra S, Bopanna MP, Bulusu V, Balaram H. Adenine metabolism in Plasmodium falciparum. Exp Parasitol 2010; 125:147-51. [PMID: 20093117 DOI: 10.1016/j.exppara.2010.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 11/11/2009] [Accepted: 01/12/2010] [Indexed: 10/19/2022]
Abstract
Plasmodium falciparum lacks the de novo purine biosynthesis pathway and relies entirely on the salvage pathway to meet its purine nucleotide requirements. The entire flux for purine nucleotide biosynthesis in the parasite is believed to be through hypoxanthine guanine phosphoribosyltransferase (HGPRT), with the enzymes, adenosine kinase and adenine phosphoribosyltransferase (APRT) being unannotated in the Plasmodium genome database. This manuscript reports on the studies carried out to explore bypass mechanisms, if any, for AMP synthesis in the intraerythrocyitc stages of the parasite life cycle. Uptake and subsequent incorporation of radiolabel adenine in the nucleotide pool of saponin released erythrocyte free parasites implicated the role of parasite encoded enzymes in adenine metabolism. To explore the route for AMP synthesis in the parasite, we have monitored adenine mediated supplementation of metabolic viability in saponin released hadacidin (N-formyl-N-hydroxyglycine) treated parasites. Our results implicate the role of an APRT like activity that enables parasite survival when the flux through the HGPRT pathway is blocked.
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Affiliation(s)
- Sonali Mehrotra
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
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8
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Cassera MB, Hazleton KZ, Riegelhaupt PM, Merino EF, Luo M, Akabas MH, Schramm VL. Erythrocytic adenosine monophosphate as an alternative purine source in Plasmodium falciparum. J Biol Chem 2008; 283:32889-99. [PMID: 18799466 DOI: 10.1074/jbc.m804497200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasmodium falciparum is a purine auxotroph, salvaging purines from erythrocytes for synthesis of RNA and DNA. Hypoxanthine is the key precursor for purine metabolism in Plasmodium. Inhibition of hypoxanthine-forming reactions in both erythrocytes and parasites is lethal to cultured P. falciparum. We observed that high concentrations of adenosine can rescue cultured parasites from purine nucleoside phosphorylase and adenosine deaminase blockade but not when erythrocyte adenosine kinase is also inhibited. P. falciparum lacks adenosine kinase but can salvage AMP synthesized in the erythrocyte cytoplasm to provide purines when both human and Plasmodium purine nucleoside phosphorylases and adenosine deaminases are inhibited. Transport studies in Xenopus laevis oocytes expressing the P. falciparum nucleoside transporter PfNT1 established that this transporter does not transport AMP. These metabolic patterns establish the existence of a novel nucleoside monophosphate transport pathway in P. falciparum.
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Affiliation(s)
- María B Cassera
- Department of Biochemistry, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York 10461, USA
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9
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de Brouwer APM, Williams KL, Duley JA, van Kuilenburg ABP, Nabuurs SB, Egmont-Petersen M, Lugtenberg D, Zoetekouw L, Banning MJG, Roeffen M, Hamel BCJ, Weaving L, Ouvrier RA, Donald JA, Wevers RA, Christodoulou J, van Bokhoven H. Arts syndrome is caused by loss-of-function mutations in PRPS1. Am J Hum Genet 2007; 81:507-18. [PMID: 17701896 PMCID: PMC1950830 DOI: 10.1086/520706] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Accepted: 06/04/2007] [Indexed: 11/03/2022] Open
Abstract
Arts syndrome is an X-linked disorder characterized by mental retardation, early-onset hypotonia, ataxia, delayed motor development, hearing impairment, and optic atrophy. Linkage analysis in a Dutch family and an Australian family suggested that the candidate gene maps to Xq22.1-q24. Oligonucleotide microarray expression profiling of fibroblasts from two probands of the Dutch family revealed reduced expression levels of the phosphoribosyl pyrophosphate synthetase 1 gene (PRPS1). Subsequent sequencing of PRPS1 led to the identification of two different missense mutations, c.455T-->C (p.L152P) in the Dutch family and c.398A-->C (p.Q133P) in the Australian family. Both mutations result in a loss of phosphoribosyl pyrophosphate synthetase 1 activity, as was shown in silico by molecular modeling and was shown in vitro by phosphoribosyl pyrophosphate synthetase activity assays in erythrocytes and fibroblasts from patients. This is in contrast to the gain-of-function mutations in PRPS1 that were identified previously in PRPS-related gout. The loss-of-function mutations of PRPS1 likely result in impaired purine biosynthesis, which is supported by the undetectable hypoxanthine in urine and the reduced uric acid levels in serum from patients. To replenish low levels of purines, treatment with S-adenosylmethionine theoretically could have therapeutic efficacy, and a clinical trial involving the two affected Australian brothers is currently underway.
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Affiliation(s)
- Arjan P M de Brouwer
- Departments of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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10
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Schuster S, Kenanov D. Adenine and adenosine salvage pathways in erythrocytes and the role of S-adenosylhomocysteine hydrolase. A theoretical study using elementary flux modes. FEBS J 2005; 272:5278-90. [PMID: 16218958 DOI: 10.1111/j.1742-4658.2005.04924.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This article is devoted to the study of redundancy and yield of salvage pathways in human erythrocytes. These cells are not able to synthesize ATP de novo. However, the salvage (recycling) of certain nucleosides or bases to give nucleotide triphosphates is operative. As the salvage pathways use enzymes consuming ATP as well as enzymes producing ATP, it is not easy to see whether a net synthesis of ATP is possible. As for pathways using adenosine, a straightforward assumption is that these pathways start with adenosine kinase. However, a pathway bypassing this enzyme and using S-adenosylhomocysteine hydrolase instead was reported. So far, this route has not been analysed in detail. Using the concept of elementary flux modes, we investigate theoretically which salvage pathways exist in erythrocytes, which enzymes belong to each of these and what relative fluxes these enzymes carry. Here, we compute the net overall stoichiometry of ATP build-up from the recycled substrates and show that the network has considerable redundancy. For example, four different pathways of adenine salvage and 12 different pathways of adenosine salvage are obtained. They give different ATP/glucose yields, the highest being 3:10 for adenine salvage and 2:3 for adenosine salvage provided that adenosine is not used as an energy source. Implications for enzyme deficiencies are discussed.
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Affiliation(s)
- Stefan Schuster
- Department of Bioinformatics, Friedrich Schiller University, Jena, Germany.
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11
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Brosh S, Zoref-Shani E, Danziger E, Bromberg Y, Sperling O, Sidi Y. Adenine nucleotide metabolism in primary rat neuronal cultures. Int J Biochem Cell Biol 1996; 28:319-28. [PMID: 8920641 DOI: 10.1016/1357-2725(95)00134-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The metabolism of adenine nucleotides (AdRN) has been studied previously in whole brains, brain slices and brain extracts, containing mixed populations of neurons and glia. The availability of primary neuronal cultures enables us to study these pathways in almost pure neuronal preparations. The aim of the present study was to characterize the relative importance of the pathways of AdRN metabolism in the neurons. The metabolic fate of (8-14C) adenine and of AdRN prelabeled with (8-14C)adenine were studied in immature and mature primary rat neuronal cultures. Specific inhibitors were used to clarify the various metabolic fluxes, which were evaluated based on the time-related changes in the distribution of label (the cellular nucleotide content did not change during incubation). The turnover rate of AdRN was found to reflect mainly conversion of label to acid insoluble derivatives (AID) and partly degradation to hypoxanthine. The turnover was faster in the immature neurons. The combined addition of 2'-deoxycoformycin (2'-dCF) and of 5'-amino-5'-deoxyadenosine, inhibiting adenosine metabolism, resulted in both cultures in enhanced loss of label from AdRN, mainly to adenosine and adenine. This finding indicates the activity of the futile cycle AMP-->adenosine-->AMP. In both cultures, in the presence of these inhibitors, the ratio (hypoxanthine + inosine)/(adenine + adenosine) was 1.1, indicating that the fluxes through AMP deamination and AMP dephosphorylation are about equal. Addition of L-alanosine, inhibiting the conversion of IMP to AMP, resulted in both cultures, but especially in the mature neurons, in enhanced loss of label from AdRN to hypoxanthine and inosine. This finding indicates the functioning of the adenine nucleotide cycle (AMP-->IMP-->adenylosuccinic acid-->AMP). Under conditions of enhanced degradation of ATP (induced by iodoacetate and antimycin A), addition of 2'-dCF resulted in the immature cultures in lowering the ratio (hypoxanthine + inosine + IMP)/(adenine + adenosine) to 0.62, indicating a shift in favor of AMP dephosphorylation.
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Affiliation(s)
- S Brosh
- Felsenstein Medical Research Center, Beilinson Medical Center, Petah Tikva, Israel
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12
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Bethlenfalvay NC, Lima JE, Banks RE. 2'-Deoxyadenosine metabolism in human and opossum Didelphis virginiana erythrocytes in vitro. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1993; 106:641-5. [PMID: 8281758 DOI: 10.1016/0305-0491(93)90142-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1. In erythrocytes of both species, deamination and phosphorylation of dADO was completely inhibited by 5 microM 2'deoxycoformycin and 10 microM 5-ITU respectively. 2. Under physiologic conditions, provided with nanomolar concentrations of dADO there was complete deamination of dADO in human red cells. In opossum erythrocytes deamination and phosphorylation of the deoxynucleoside were nearly; additionally, 1-2% of the substrate was metabolized to AXP. 3. With ADA inhibited in intact red cells, apparent Km and Vmax for dADO were 0.5 vs 0.1 mM and 0.8 vs 6.25 mumol/g hg/hr in human and opossum cells, respectively. 4. In opossum red cell lysates, GTP was superior to ATP and to dATP as a phosphate donor in the dADO kinase reaction.
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Affiliation(s)
- N C Bethlenfalvay
- Department of Primary Care, Fitzimons Army Medical Center, Aurora, CO 80045
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13
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Smolenski RT, Fabianowska-Majewska K, Montero C, Duley JA, Fairbanks LD, Marlewski M, Simmonds HA. A novel route of ATP synthesis. Biochem Pharmacol 1992; 43:2053-7. [PMID: 1599494 DOI: 10.1016/0006-2952(92)90161-b] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Incorporation of the adenine moiety of 2'-deoxyadenosine (dAdo) into ATP, consistently observed in human erythrocytes, is a phenomenon which cannot be explained by the operation of any known pathway. We reported previously that this effect was not observed in adenine phosphoribosyltransferase-deficient erythrocytes showing that adenine must be an obligatory intermediate. However, generation of adenine from dAdo was difficult to reconcile with the operation of any known process in human cells, and involvement of S-adenosylhomocysteine hydrolase (SAH-hydrolase) was postulated. The present studies with intact human erythrocytes demonstrate that nucleoside analogues which inhibit SAH-hydrolase caused substantial attenuation of adenine transfer from dAdo into ATP. It was confirmed that dAdo is not a substrate of 5'deoxy-5'methylthioadenosine (5'MT-adenosine) phosphorylase. Inhibition of the transfer of the adenine moiety of dAdo into ATP did not correlate with inhibition of 5'MT-adenosine phosphorylase by nucleoside analogues. This report provides further evidence that the pathway involving nucleoside (adenosine) analogue binding to SAH-hydrolase, release of base and subsequent phosphoribosylation can operate in intact cells. The metabolic significance of this process relates to the possible generation of free bases (adenine) in the human body, ATP synthesis and nucleoside drug interconversions.
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Affiliation(s)
- R T Smolenski
- Purine Research Laboratory, UMDS Guy's Hospital, London Bridge, London, U.K
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14
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Smolenski RT, Montero C, Duley JA, Simmonds HA. Effects of adenosine analogues on ATP concentrations in human erythrocytes. Further evidence for a route independent of adenosine kinase. Biochem Pharmacol 1991; 42:1767-73. [PMID: 1930301 DOI: 10.1016/0006-2952(91)90514-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Adenosine derivatives are frequently used in chemotherapy because of their potent antitumor, antiviral and antiparasitic activity. We investigated the metabolism of some adenosine analogues in adenosine deaminase inhibited normal and adenine phosphoribosyltransferase (APRT) deficient human erythrocytes. The ATP and GTP concentrations and the formation of unusual nucleotides were measured. Some of the analogues studied (tubercidin, 9 beta-D-arabinofuranosyladenine, 2'-deoxyadenosine, 2-chloroadenosine, neplanocin A) were phosphorylated to the corresponding nucleoside triphosphates and this process was abolished by iodotubercidin--an adenosine kinase inhibitor. With the exception of 2'-deoxyadenosine, nucleotide analogue formation was accompanied by ATP depletion. ATP decrease was not observed after adenosine kinase inhibition and ATP concentration even increased in the presence of 2'-deoxyadenosine, neplanocin A and 5'-iodo-5'-deoxyadenosine. However, the latter increment was not observed in APRT deficient erythrocytes. Bredinin, S-adenosylhomocysteine, deoxycoformycin and adenosine dialdehyde did not form nucleotide derivatives or exert any effects on ATP concentration. It is concluded that adenosine analogues can either enter the nucleotide pool via phosphorylation mechanisms, or may be converted to ATP by the pathways involving the intermediate formation of adenine.
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Affiliation(s)
- R T Smolenski
- Purine Research Laboratory, Clinical Science Laboratories, UMDS Guy's Hospital, London, U.K
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Kaneko K, Fujimori S, Kumakawa T, Kamatani N, Akaoka I. Disturbance in the metabolism of 5'-methylthioadenosine and adenine in patients with neoplastic diseases, and in those with a deficiency in adenine phosphoribosyltransferase. Metabolism 1991; 40:918-21. [PMID: 1895956 DOI: 10.1016/0026-0495(91)90066-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
5'-Methylthioadenosine (MTA) produced during the synthesis of polyamines is degraded to adenine by MTA phosphorylase. This pathway is considered to be the main source of endogenous adenine. We determined the concentrations of MTA and adenine in control subjects and in those with a pathological disorder. In patients with active leukemias, as well as with other types of malignancies, the concentrations of MTA and adenine in the urine were elevated. These changes seemed to be the result of an accelerated production of MTA due to an accelerated biosynthesis of polyamine. In patients with adenine phosphoribosyltransferase (APRT) deficiency, the concentrations of adenine in the urine were elevated, presumably due to a disturbance in the catabolism of adenine. Although adenine is a potent inhibitor of MTA phosphorylase, APRT-deficient patients did not excrete MTA into urine in concentrations significantly larger than noted for control subjects. However, the amount of MTA excreted positively correlated with that of adenine in these patients, hence that accumulated adenine probably had a slight, but positive, inhibitory effect on the degradation of MTA.
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Affiliation(s)
- K Kaneko
- Central Laboratory of Analytical Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
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Montero C, Smolenski RT, Duley JA, Simmonds HA. An alternative pathway of adenylate and ATP synthesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 309A:285-8. [PMID: 1789227 DOI: 10.1007/978-1-4899-2638-8_64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- C Montero
- Purine Research Laboratory, UMDS Guy's Hospital, London, U.K
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Montero C, Smolenski RT, Duley JA, Simmonds HA. S-adenosylmethionine increases erythrocyte ATP in vitro by a route independent of adenosine kinase. Biochem Pharmacol 1990; 40:2617-23. [PMID: 2260986 DOI: 10.1016/0006-2952(90)90579-a] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The mechanism by which S-adenosylmethionine (SAM) and adenosine (Ado) increase ATP levels in intact human erythrocytes in vitro has been compared. The use of erythrocytes from healthy controls and from subjects totally deficient in adenine phosphoribosyltransferase (APRT), plus inhibitors of adenosine kinase (AK) and adenosine deaminase (ADA) separately and together, has enabled us to demonstrate that this increment in ATP levels occurred via totally different metabolic routes. The results show that: (i) whilst the Ado-induced increment in ATP was AK dependent, that produced by SAM was independent of AK: and (ii) the SAM-induced increment in ATP was totally dependent on APRT and that some of the increment produced by Ado might also be APRT dependent. The above data are consistent with the metabolism of SAM to ATP by a route recently identified by us whereby ATP is formed from deoxyadenosine: namely binding to the enzyme S-adenosylhomocysteine hydrolase with subsequent release of adenine and further conversion to ATP via APRT.
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Affiliation(s)
- C Montero
- Purine Research Laboratory, UMDS Guy's Hospital, London Bridge, U.K
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