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Di Stefano M, Galassi L, Magni G. Unique expression pattern of human nicotinamide mononucleotide adenylyltransferase isozymes in red blood cells. Blood Cells Mol Dis 2010; 45:33-9. [PMID: 20457531 DOI: 10.1016/j.bcmd.2010.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Revised: 04/09/2010] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
Abstract
Nicotinamide mononucleotide adenylyltransferase (NMNAT) catalyzes the formation of nicotinamide adenine dinucleotide (NAD). In humans, three isozymes have been identified: NMNAT1, which is widely expressed in all tissues, NMNAT2 and NMNAT3, which show a tissue-specific expression and whose mRNA levels are generally lower compared to NMNAT1. In the present study we determined the individual NMNAT isozymes activity in human red blood cells (RBCs) by using a biochemical discrimination assay based on the distinctive catalytic properties of the three proteins. We found that isozyme 3 predominates over isozyme 1, whereas isozyme 2 is absent. This high prevalence of NMNAT3 is cell-aging independent and was also confirmed by analyzing the mRNA and protein levels. RBC represent the first human cell type with a remarkable predominance of NMNAT3, and this unique expression pattern is discussed in light of the catalytic properties of the isozymes and in consideration of the biochemical microenvironment of RBC.
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Affiliation(s)
- M Di Stefano
- Dipartimento di Patologia Molecolare e Terapie Innovative, sezione di Biochimica, Università Politecnica delle Marche, Via Ranieri 69, 60131 Ancona, Italy
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2
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Zhang X, Kurnasov OV, Karthikeyan S, Grishin NV, Osterman AL, Zhang H. Structural characterization of a human cytosolic NMN/NaMN adenylyltransferase and implication in human NAD biosynthesis. J Biol Chem 2003; 278:13503-11. [PMID: 12574164 DOI: 10.1074/jbc.m300073200] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pyridine dinucleotides (NAD and NADP) are ubiquitous cofactors involved in hundreds of redox reactions essential for the energy transduction and metabolism in all living cells. In addition, NAD also serves as a substrate for ADP-ribosylation of a number of nuclear proteins, for silent information regulator 2 (Sir2)-like histone deacetylase that is involved in gene silencing regulation, and for cyclic ADP ribose (cADPR)-dependent Ca(2+) signaling. Pyridine nucleotide adenylyltransferase (PNAT) is an indispensable central enzyme in the NAD biosynthesis pathways catalyzing the condensation of pyridine mononucleotide (NMN or NaMN) with the AMP moiety of ATP to form NAD (or NaAD). Here we report the identification and structural characterization of a novel human PNAT (hsPNAT-3) that is located in the cytoplasm and mitochondria. Its subcellular localization and tissue distribution are distinct from the previously identified human nuclear PNAT-1 and PNAT-2. Detailed structural analysis of PNAT-3 in its apo form and in complex with its substrate(s) or product revealed the catalytic mechanism of the enzyme. The characterization of the cytosolic human PNAT-3 provided compelling evidence that the final steps of NAD biosynthesis pathways may exist in mammalian cytoplasm and mitochondria, potentially contributing to their NAD/NADP pool.
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Affiliation(s)
- Xuejun Zhang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
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3
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Sandmeier JJ, Celic I, Boeke JD, Smith JS. Telomeric and rDNA silencing in Saccharomyces cerevisiae are dependent on a nuclear NAD(+) salvage pathway. Genetics 2002; 160:877-89. [PMID: 11901108 PMCID: PMC1462005 DOI: 10.1093/genetics/160.3.877] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Sir2 protein is an NAD(+)-dependent protein deacetylase that is required for silencing at the silent mating-type loci, telomeres, and the ribosomal DNA (rDNA). Mutations in the NAD(+) salvage gene NPT1 weaken all three forms of silencing and also cause a reduction in the intracellular NAD(+) level. We now show that mutation of a highly conserved histidine residue in Npt1p results in a silencing defect, indicating that Npt1p enzymatic activity is required for silencing. Deletion of another NAD(+) salvage pathway gene called PNC1 caused a less severe silencing defect and did not significantly reduce the intracellular NAD(+) concentration. However, silencing in the absence of PNC1 was completely dependent on the import of nicotinic acid from the growth medium. Deletion of a gene in the de novo NAD(+) synthesis pathway BNA1 resulted in a significant rDNA silencing defect only on medium deficient in nicotinic acid, an NAD(+) precursor. By immunofluorescence microscopy, Myc-tagged Bna1p was localized throughout the whole cell in an asynchronously growing population. In contrast, Myc-tagged Npt1p was highly concentrated in the nucleus in approximately 40% of the cells, indicating that NAD(+) salvage occurs in the nucleus in a significant fraction of cells. We propose a model in which two components of the NAD(+) salvage pathway, Pnc1p and Npt1p, function together in recycling the nuclear nicotinamide generated by Sir2p deacetylase activity back into NAD(+).
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Affiliation(s)
- Joseph J Sandmeier
- Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908, USA.
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Magni G, Amici A, Emanuelli M, Raffaelli N, Ruggieri S. Enzymology of NAD+ synthesis. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 1999; 73:135-82, xi. [PMID: 10218108 DOI: 10.1002/9780470123195.ch5] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Beyond its role as an essential coenzyme in numerous oxidoreductase reactions as well as respiration, there is growing recognition that NAD+ fulfills many other vital regulatory functions both as a substrate and as an allosteric effector. This review describes the enzymes involved in pyridine nucleotide metabolism, starting with a detailed consideration of the anaerobic and aerobic pathways leading to quinolinate, a key precursor of NAD+. Conversion of quinolinate and 5'-phosphoribosyl-1'-pyrophosphate to NAD+ and diphosphate by phosphoribosyltransferase is then explored before proceeding to a discussion the molecular and kinetic properties of NMN adenylytransferase. The salient features of NAD+ synthetase as well as NAD+ kinase are likewise presented. The remainder of the review encompasses the metabolic steps devoted to (a) the salvaging of various niacin derivatives, including the roles played by NAD+ and NADH pyrophosphatases, nicotinamide deamidase, and NMN deamidase, and (b) utilization of niacins by nicotinate phosphoribosyltransferase and nicotinamide phosphoribosyltransferase.
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Affiliation(s)
- G Magni
- Istituto di Biochimica, Facoltà di Medicina, Università di Ancona, Italy
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Magni G, Raffaelli N, Emanuelli M, Amici A, Natalini P, Ruggieri S. Nicotinamide-mononucleotide adenylyltransferases from yeast and other microorganisms. Methods Enzymol 1997; 280:248-55. [PMID: 9211320 DOI: 10.1016/s0076-6879(97)80116-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- G Magni
- Istituto di Biochimica, Facoltà di Medicina, Università di Ancona, Italy
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6
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Balducci E, Orsomando G, Polzonetti V, Vita A, Emanuelli M, Raffaelli N, Ruggieri S, Magni G, Natalini P. NMN adenylyltransferase from bull testis: purification and properties. Biochem J 1995; 310 ( Pt 2):395-400. [PMID: 7654174 PMCID: PMC1135908 DOI: 10.1042/bj3100395] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The purification procedure of NMN adenylyltransferase from bull testis presented here consists of a heat step and an acidic precipitation followed by four chromatographic steps, including dye ligand, adsorption and hydrophobic chromatography. The final enzyme preparation subjected to non-denaturing and denaturating PAGE with silver nitrate staining exhibited a single band. At this step the enzyme appeared to be homogeneous. The M(r) value of the native enzyme calculated by gel filtration was about 133,000. The protein appeared to possess a quaternary structure with four subunits of apparent M(r) 33,000 without disulphide interchain bonds. Isoelectric experiments gave a pI of 6.2, and pH studies showed the possible presence of an acidic group in the active site having a pKa of 4.9. Analysis of the amino acid composition showed the presence of more acidic residues than basic ones, according to the pI value calculated by Mono P FPLC. The Ea calculated by Arrhenius plot gave an apparent value of 55.7 kJ/mol. The Km values for NMN, ATP, NAD+ and PPi were 0.11, 0.023, 0.37 and 0.16 nM respectively. The polyclonal antiserum produced against the NMN adenylyltransferase reacted with the purified enzyme at different dilutions and recognized the enzyme in the homogenate as well.
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Affiliation(s)
- E Balducci
- Dipartimento di Biologia M. C. A., Università di Camerino, Italy
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7
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Raffaelli N, Amici A, Emanuelli M, Ruggieri S, Magni G. Pyridine dinucleotide biosynthesis in archaebacteria: presence of NMN adenylyltransferase in Sulfolobus solfataricus. FEBS Lett 1994; 355:233-6. [PMID: 7988679 DOI: 10.1016/0014-5793(94)01195-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The enzyme NMN adenylyltransferase, leading to NAD synthesis, has been observed for the first time in soluble extracts from the extreme acidothermophilic archaeon Sulfolobus solfataricus. Comparison of its molecular and kinetic properties with those of the enzyme isolated from prokaryotes and eukaryotes revealed significant differences, knowledge of which may contribute to the understanding of metabolic evolutionary mechanisms. The thermophilic enzyme shows a molecular mass of about 66,000 and an isoelectric point of 5.4. The Km values for ATP, NMN and nicotinic acid mononucleotide are 0.08 microM, 1.4 microM and 17 microM, respectively. The enzyme shows a remarkable degree of thermophilicity, with an activation energy of 95 kJ/mol.
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Affiliation(s)
- N Raffaelli
- Istituto di Biochimica, Facoltà di Medicina e Chirurgia, Università di Ancona, Italy
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8
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Emanuelli M, Natalini P, Raffaelli N, Ruggieri S, Vita A, Magni G. NAD biosynthesis in human placenta: purification and characterization of homogeneous NMN adenylyltransferase. Arch Biochem Biophys 1992; 298:29-34. [PMID: 1524439 DOI: 10.1016/0003-9861(92)90089-f] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Nicotinamide mononucleotide (NMN) adenylyltransferase has been purified to homogeneity from human placenta. The purification procedure consists of several chromatographic steps, including dye-ligand, adsorption, and hydrophobic interaction chromatography. The final enzyme preparation is homogeneous as judged by a single silver stainable band on both nondenaturating and denaturating polyacrylamide gels. The native enzyme shows a molecular weight of about 132,000, as determined by gel filtration on a Superose 12 HR 10/30 fast protein liquid chromatography column. The protein possesses a quaternary structure and is composed of four apparently identical M(r) 33,000 subunits. Isoelectrofocusing experiments give multiple pI values ranging from pH 4.7 to 6.6. Optimum pH study shows a plateau extending from pH 6.0 to pH 9.0. Km values for NMN, ATP, NAD+, and PPi are 38, 23, 67, and 125 microM, respectively. Kinetic analysis reveals a behavior consistent with an ordered sequential Bi-Bi mechanism. Among several metabolites tested only ADP-ribose and beta-NMNH were found to significantly inhibit the enzyme activity.
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Affiliation(s)
- M Emanuelli
- Istituto di Biochimica, Facoltà di Medicinae Chirurgia, Università di Ancona, Italy
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Emanuelli M, Raffaelli N, Ruggieri S, Natalini P, Magni G. Pyridine nucleotide metabolism: purification and properties of NMN adenylyltransferase from human placenta. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 309B:333-6. [PMID: 1781391 DOI: 10.1007/978-1-4615-7703-4_74] [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)
- M Emanuelli
- Istituto di Biochimica, Università di Ancona, Italy
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Shibata K, Hayakawa T, Taguchi H, Iwai K. Regulation of pyridine nucleotide coenzyme metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 294:207-18. [PMID: 1837681 DOI: 10.1007/978-1-4684-5952-4_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- K Shibata
- Teikoku Women's University Moriguchi, Osaka, Japan
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Abstract
Nicotinamide mononucleotide (NMN) is not only an intermediate for the biosynthesis but also a degradation product of pyridine cofactors in animal tissues. Among the animal tissues tested, the highest NMN catabolizing activity was detected in beef liver (5.6 mumol/min/g tissue). This activity was 16 times higher than the NAD hydrolysis catalyzed by the liver NAD glycohydrolase. As a result of enzymatic analysis of the NMN splitting process, two types of enzyme responsible for this catabolism were partially purified and identified as a membrane-bound 5'-nucleotidase and a cytoplasmic nicotinamide riboside (NR) phosphorylase. No specific NMN glycohydrolase could be found in contrast to results observed in bacterial systems. The 5'-nucleotidase and NR phosphorylase constitute an obligatory process of the pyridine nucleotide cycle. The dephosphorylation and phosphorolysis catalyzed suggest that these enzymes could serve as an important mechanism for salvaging the ribose and nicotinamide moieties of NMN and pyridine nucleotides in the cell and a process that could be regulated at the mononucleotide level by this "NMN cycle" rather than by a NAD glycohydrolase cycle. In addition to the enzymatic properties of these enzymes, a regulatory mechanism by nucleotides such as ATP was also demonstrated.
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Kucera R, Paulus H. Localization of the deoxyribonucleotide biosynthetic enzymes ribonucleotide reductase and thymidylate synthase in mouse L cells. Exp Cell Res 1986; 167:417-28. [PMID: 3533576 DOI: 10.1016/0014-4827(86)90182-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Two different approaches were used to define the intracellular localization in mouse L929 cells of two deoxyribonucleotide biosynthetic enzymes: ribonucleoside diphosphate reductase (EC1.17.4.1) and thymidylate synthase (EC2.1.1.45). The first involved treatment with saponins, which render the plasma membrane permeable to proteins without disrupting intracellular organelles. Under conditions where nuclear DNA synthesis and the activity of the nuclear enzyme NMN adenylyltransferase were unaffected, the entire cellular complements of a cytosolic enzyme, glucose-6-phosphate dehydrogenase, and of ribonucleotide reductase and thymidylate synthase were released at the same rate and with similar dependence on saponin concentration. The second approach involved centrifugal enucleation of cells treated with cytochalasin B (CB) and measurement of the distribution of enzyme activities in the resulting cytoplast and karyoplast fractions. Whereas most NMN adenylyltransferase activity remained with the karyoplasts, glucose-6-phosphate dehydrogenase, ribonucleotide reductase, and thymidylate synthase were almost exclusively associated with the enucleated cytoplasts. These results indicate that, under conditions where nuclear DNA synthesis is apparently unperturbed, the intracellular distribution of the deoxyribonucleotide biosynthetic enzymes studied is the same as that of glucose-6-phosphate dehydrogenase, a typical cytosol enzyme, and clearly differs from that of NMN adenylyltransferase, a nuclear enzyme.
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Uhr ML, Smulson M. NMN adenylyltransferase: its association with chromatin and with poly(ADP-ribose) polymerase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1982; 128:435-43. [PMID: 6295757 DOI: 10.1111/j.1432-1033.1982.tb06983.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The nuclear location of NMN adenylytransferase, which catalyses the formation of NAD and pyrophosphate from ATP and NMN, has been examined to ascertain if the enzyme is bound to the domains of chromatin which undergo poly(ADP-ribos)ylation. This latter reaction utilizes much of the cellular NAD. A radioisotope assay using [alpha-32P]ATP was developed to enable precise measurement of picomole amounts of NAD. With this assay, it appeared that the reaction catalysed by NMN adenylyltransferase proceeded with a rapid, early 'burst' of NAD before steady-state velocities were established. From this it was calculated that there could be 10- active sites of NMN adenylyltransferase per HeLa nucleus in asynchronously growing cells: that is, approximately one per 10-20 nucleosomes. Very little enzyme activity was liberated by digesting HeLa nuclei with micrococcal nuclease in 80 mM NaCl, and the enzyme which was solubilized was not bound to oligonucleosomes separated by electrophoresis on polyacrylamide gels. In contrast, poly(ADP-ribose) polymerase activity was clearly demonstrated on these particles. The enzyme was readily liberated by DNase I digestion, especially when the digestion was carried out in low-ionic-strength buffer. The results demonstrated that the enzyme was neither bound to oligonucleosomes nor part of the nuclear envelope or matrix. Preliminary results suggested that there could be some direct channelling of NAD between the two enzymes in intact nuclei. It appears that NMN adenylyltransferase is bound within rather than to chromatin.
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Cartwright IL, Abmayr SM, Fleischmann G, Lowenhaupt K, Elgin SC, Keene MA, Howard GC. Chromatin structure and gene activity: the role of nonhistone chromosomal proteins. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1982; 13:1-86. [PMID: 6751690 DOI: 10.3109/10409238209108709] [Citation(s) in RCA: 154] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Cantarow W, Stollar BD. Nicotinamide mononucleotide adenylyltransferase, a nonhistone chromatin protein. Immunochemical comparative studies. Arch Biochem Biophys 1977; 180:34-40. [PMID: 856044 DOI: 10.1016/0003-9861(77)90005-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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