1
|
Paneque A, Fortus H, Zheng J, Werlen G, Jacinto E. The Hexosamine Biosynthesis Pathway: Regulation and Function. Genes (Basel) 2023; 14:genes14040933. [PMID: 37107691 PMCID: PMC10138107 DOI: 10.3390/genes14040933] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
The hexosamine biosynthesis pathway (HBP) produces uridine diphosphate-N-acetyl glucosamine, UDP-GlcNAc, which is a key metabolite that is used for N- or O-linked glycosylation, a co- or post-translational modification, respectively, that modulates protein activity and expression. The production of hexosamines can occur via de novo or salvage mechanisms that are catalyzed by metabolic enzymes. Nutrients including glutamine, glucose, acetyl-CoA, and UTP are utilized by the HBP. Together with availability of these nutrients, signaling molecules that respond to environmental signals, such as mTOR, AMPK, and stress-regulated transcription factors, modulate the HBP. This review discusses the regulation of GFAT, the key enzyme of the de novo HBP, as well as other metabolic enzymes that catalyze the reactions to produce UDP-GlcNAc. We also examine the contribution of the salvage mechanisms in the HBP and how dietary supplementation of the salvage metabolites glucosamine and N-acetylglucosamine could reprogram metabolism and have therapeutic potential. We elaborate on how UDP-GlcNAc is utilized for N-glycosylation of membrane and secretory proteins and how the HBP is reprogrammed during nutrient fluctuations to maintain proteostasis. We also consider how O-GlcNAcylation is coupled to nutrient availability and how this modification modulates cell signaling. We summarize how deregulation of protein N-glycosylation and O-GlcNAcylation can lead to diseases including cancer, diabetes, immunodeficiencies, and congenital disorders of glycosylation. We review the current pharmacological strategies to inhibit GFAT and other enzymes involved in the HBP or glycosylation and how engineered prodrugs could have better therapeutic efficacy for the treatment of diseases related to HBP deregulation.
Collapse
Affiliation(s)
- Alysta Paneque
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Harvey Fortus
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Julia Zheng
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Guy Werlen
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| |
Collapse
|
2
|
Ruiz M, Cejudo F, Muñoz-Centeno M, Paneque A. Isolation and characterization of an Azotobacter chroococcum mutant deficient in nitrate transport. FEMS Microbiol Lett 2006. [DOI: 10.1111/j.1574-6968.1990.tb13865.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
3
|
Reguera E, Balmaseda J, Fernández-Bertrán J, Paneque A, Yee-Madeira H. Complex Formation of Ferric Protoporphyrin IX From the Reaction of Hemin with Ammonia and Small Aliphatic Amines. TRANSIT METAL CHEM 2004. [DOI: 10.1023/b:tmch.0000027455.71173.d3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
4
|
Peciña A, Pascual A, Paneque A. Cloning and expression of the algL gene, encoding the Azotobacter chroococcum alginate lyase: purification and characterization of the enzyme. J Bacteriol 1999; 181:1409-14. [PMID: 10049370 PMCID: PMC93528 DOI: 10.1128/jb.181.5.1409-1414.1999] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The alginate lyase-encoding gene (algL) of Azotobacter chroococcum was localized to a 3.1-kb EcoRI DNA fragment that revealed an open reading frame of 1,116 bp. This open reading frame encodes a protein of 42.98 kDa, in agreement with the value previously reported by us for this protein. The deduced protein has a potential N-terminal signal peptide that is consistent with its proposed periplasmic location. The analysis of the deduced amino acid sequence indicated that the gene sequence has a high homology (90% identity) to the Azotobacter vinelandii gene sequence, which has very recently been deposited in the GenBank database, and that it has 64% identity to the Pseudomonas aeruginosa gene sequence but that it has rather low homology (15 to 22% identity) to the gene sequences encoding alginate lyase in other bacteria. The A. chroococcum AlgL protein was overproduced in Escherichia coli and purified to electrophoretic homogeneity in a two-step chromatography procedure on hydroxyapatite and phenyl-Sepharose. The kinetic and molecular parameters of the recombinant alginate lyase are similar to those found for the native enzyme.
Collapse
Affiliation(s)
- A Peciña
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Seville, Spain
| | | | | |
Collapse
|
5
|
Paneque A, Torres AI, Camacho MA. High performance liquid chromatographic method for the determination of lobenzarit disodium in a sustained release tablet formulation. Arzneimittelforschung 1998; 48:832-5. [PMID: 9748712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A rapid and simple high performance liquid chromatographic method is described and validated for the determination of lobenzarit disodium (CAS 64808-48-6) in a sustained release tablet formulation. The calibration graph was linear over the range 20-105 micrograms/ml. The sensitivity (discriminator capacity) was 2.079 micrograms/ml. The coefficient of variations for repeatability and reproducibility were less than 1.60% and 1.30%, respectively. The accuracy of the method did not depend on lobenzarit concentration in tablets. The mean recovery was found to be 100.62%. The method was selective, even when degradation products were present.
Collapse
Affiliation(s)
- A Paneque
- Center of Pharmaceutical Chemistry, Havana, Cuba
| | | | | |
Collapse
|
6
|
Abstract
Nitrogen-fixing Azotobacter chroococcum cells, but not ammonium- or nitrate-grown cells, exhibited two polypeptide components of 22 and 35 kDa, respectively, that we termed P22 and P35. Bidimensional polyacrylamide gel electrophoresis analysis of preparations from N2-fixing cells that had been transferred to nitrate medium and then incubated for 2 h revealed that P22 had shifted to a more acidic part of the gel while P35 did not change its electrophoretic pattern. Using [32P]orthophosphoric acid it could be demonstrated that the shift in mobility of P22 was due to the phosphorylation of the polypeptide dependent on nitrate (nitrite). The A. chroococcum TR1 strain, which is unable to use nitrate as a nitrogen source and displays activities of nitrogenase, nitrate reductase and nitrite reductase, exhibited both polypeptides. In contrast, P22 and P35 were absent from A. chroococcum MCD1, a mutant strain that cannot assimilate nitrate and lacks the nitrate-reducing enzymatic system. The results suggest that P22 could act as a sensor protein for nitrate in A. chroococcum.
Collapse
Affiliation(s)
- M C Muñoz-Centeno
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas, Spain
| | | | | | | |
Collapse
|
7
|
Muñoz-Centeno MC, Ruiz MT, Paneque A, Cejudo FJ. Posttranslational regulation of nitrogenase activity by fixed nitrogen in Azotobacter chroococcum. Biochim Biophys Acta 1996; 1291:67-74. [PMID: 8781527 DOI: 10.1016/0304-4165(96)00045-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Using anti-(Fe protein) antibody raised against the Fe protein of the photosynthetic bacterium Rhodospirillum rubrum, it was found that the Fe protein component of nitrogenase (EC 1.18.2.1) from Azotobacter chroococcum cells subjected to an ammonium shock, and hence with an inactive nitrogenase, appeared as a doublet in Western blot analysis of cell extracts. The Fe protein incorporated [32P]phosphate and [3H]adenine in response to ammonium treatment, and L-methionine-DL-sulfoximine, an inhibitor of glutamine synthetase (L-glutamate: ammonia ligase (ADP forming), EC 6.3.1.2), prevented Fe protein from inhibition and radioisotope labelling. These results support that A. chroococcum Fe protein is most likely ADP-ribosylated in response to ammonium. After ammonium treatment, when in vivo activity was completely inhibited, Fe-protein modification was still increasing. This suggests the existence of another mechanism of nitrogenase inhibition faster than Fe-protein modification. When ammonium was intracellularly generated instead of being externally added, as occurs with the short-term nitrate inhibition of nitrogenase activity observed in A. chroococcum cells simultaneously fixing molecular nitrogen and assimilating nitrate, a covalent modification of the Fe protein was likewise demonstrated.
Collapse
Affiliation(s)
- M C Muñoz-Centeno
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas, Facultad de Biología, Spain
| | | | | | | |
Collapse
|
8
|
Pecina A, Paneque A. Studies on some enzymes of alginic acid biosynthesis in mucoid and nonmucoidAzotobacter chroococcum strains. Appl Biochem Biotechnol 1994. [DOI: 10.1007/bf02888847] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
9
|
Abstract
A monospecific anti-(glutamine synthetase) antibody raised against glutamine synthetase of the unicellular cyanobacterium Synechocystis sp. strain PCC 6803 immunoreacted with glutamine synthetase from the N2-fixing heterotrophic bacterium Azotobacter chroococcum. In Western-blotting experiments this antibody recognized a single protein of a molecular mass of 59 kDa corresponding to glutamine synthetase subunit. This protein was in vivo-labelled in response to addition of ammonium, both [3H]adenine and H(3)32PO4 preincubation of the cells being equally effective. Nevertheless, the amount of glutamine synthetase present in A. chroococcum was independent of the available nitrogen source. Modified, inactive glutamine synthetase was re-activated by treatment with snake-venom phosphodiesterase but not by alkaline phosphatase. L-Methionine-DL-sulphoximine, an inhibitor of glutamine synthetase, prevented the enzyme from being covalently modified. We conclude that, in A. chroococcum, glutamine synthetase is adenylylated in response to ammonium and that for the modification to take place ammonium must be metabolized.
Collapse
Affiliation(s)
- M C Muñoz-Centeno
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas, Spain
| | | | | |
Collapse
|
10
|
Peciña A, Paneque A. Detection of alginate lyase by activity staining after sodium dodecil sulfate-polyacrylamide gel electrophoresis and subsequent renaturation. Anal Biochem 1994; 217:124-7. [PMID: 7515596 DOI: 10.1006/abio.1994.1092] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A slab gel electrophoretic method for the study of bacterial alginate lyase has been developed. By incorporating alginate in acrylamide gels, the method is based on renaturation of the enzyme after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, subsequent staining with cetylpyridinium chloride, and quantification of the spot by densitometric scanning. The molecular mass of alginate lyase can be determined from its position in the gel.
Collapse
Affiliation(s)
- A Peciña
- Instituto de Bioquimica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas, Spain
| | | |
Collapse
|
11
|
Muñoz-Centeno M, Cejudo F, Ruiz M, Paneque A. The Azotobacter chroococcum nitrate permease is a multicomponent system. Biochimica et Biophysica Acta (BBA) - Bioenergetics 1993. [DOI: 10.1016/0005-2728(93)90191-h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
12
|
Abstract
Environmental conditions affect the production of extracellular polysaccharide by Azotobacter chroococcum ATCC 4412. Production of exocellular polymer from a variety of carbon sources depended on the air flow rate. A high sucrose concentration in medium (8%) markedly favored expopolysaccharide production, which reached 14 g/L in about 72 h. In cell suspensions incubated in the presence of 8% sucrose in a nitrogen-free medium, biopolymer final concentration of 9 g/L corresponds to 68 g/g biomass. Maximum efficiency of sucrose conversion into exopolysaccharide peaked at 70% for initial disaccharide concentration of 6%. High performance liquid chromatography and gas liquid chromatography of acid hydrolysates of the exopolymer revealed the presence of mannuronosyl, guluronosyl, and acetyl residues, but not neutral sugars. The infrared spectrum corroborated the presence of carboxylate anions and O-acetyl groups in the exopolymer. Though the presence of more than one kind of polysaccharide cannot be ruled out, these data suggest that, under the experimental conditions used in this work, only a type of alginate-like exopolysaccharide is produced by A. chroococcum ATCC 4412.
Collapse
Affiliation(s)
- M G De la Vega
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas, Spain
| | | | | |
Collapse
|
13
|
Caraballoso Hernández M, Granda Ibarra A, Cabrera Trujillo JF, del Puerto Quintana C, Hernández Ceballos H, Martínez Calvo S, Paneque A, Rodríguez Hernández P, Toledo Corbelo G. [General aspects of the national program for training specialists in hygiene and epidemiology in Cuba]. Educ Med Salud 1990; 24:280-94. [PMID: 2276369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
14
|
Cejudo F, Paneque A. Correlation between nitrate uptake rate and nitrate inhibition of nitrogenase activity in Azotobacter chroococcum. FEMS Microbiol Lett 1987. [DOI: 10.1111/j.1574-6968.1987.tb02088.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
15
|
Revilla E, Llobell A, Paneque A. Energy-dependence of the Assimilatory Nitrate Uptake in Azotobacter chroococcum. Microbiology (Reading) 1986. [DOI: 10.1099/00221287-132-4-917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
16
|
Abstract
Nitrate-grown Azotobacter chroococcum ATCC 4412 cells lack the ability to fix N2. Nitrogenase activity developed after the cells were suspended in a combined nitrogen-free medium and was paralleled by a concomitant decrease in nitrate assimilation capacity. In such treated cells exhibiting transitory nitrate assimilation and N2-fixation capacity, nitrate or nitrite caused a short-term inhibitory effect on nitrogenase activity which ceased once the anion was exhausted from the medium. The analog L-methionine-DL-sulfoximine, an inhibitor of glutamine synthetase, prevented inhibition of nitrogenase activity by nitrate or nitrite without affecting the uptake of these antions, which were reduced and stoichiometrically released into the external medium as ammonium. Inhibition of nitrogenase by nitrate (nitrite) did not take place in A. chroococcum MCD1, which is unable to assimilate either. We conclude that the short-term inhibitory effect of nitrate (nitrite) on nitrogenase activity is due to some organic product(s) formed during the assimilation of the ammonium resulting from nitrate (nitrite) reduction.
Collapse
|
17
|
Abstract
Addition of NH4Cl at low concentrations to Azotobacter chroococcum cells caused an immediate cessation of nitrogenase activity, which was recovered once the added NH+4 was exhausted from the medium. In the presence of inhibitors of ammonium assimilation, such as L-methionine-DL-sulfoximine, L-methionine sulfone or 6-diazo-5-oxo-L-norleucine, externally added NH+4 had no effect on nitrogenase activity and the newly-fixed nitrogen was excreted into the medium as NH+4. It is concluded that, in A. chroococcum, NH+4 must be assimilated to exert its short-term inhibitory effect on nitrogen fixation.
Collapse
|
18
|
Paneque A, Bárcena JA, Cordero N, Revilla E, Llobell A. Benzyl viologen-mediated in vivo and in vitro inactivation of glutamine synthetase in Azotobacter chroococcum. Mol Cell Biochem 1982; 49:33-41. [PMID: 6129569 DOI: 10.1007/bf00230993] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
19
|
Llobell A, Bárcena J, Vila R, Paneque A. Flavin-Mediated Photoreduction of Nitrate by Nitrate Reductase from Azotobacter chroococcum. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/s0044-328x(80)80277-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
20
|
Vila R, Llobell A, Bárcena JA, Paneque A. Nitrate reductase from Azotobacter chroococcum. Inactivation by oxidizing agents and reactivation with dithioerythritol. Biochem Biophys Res Commun 1978; 84:943-9. [PMID: 728161 DOI: 10.1016/0006-291x(78)91674-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
21
|
Vila R, Bárcena JA, Llobell A, Paneque A. Characterization of a membrane-bound nitrate reductase from Azotobacter chroococcum. Biochem Biophys Res Commun 1977; 75:682-8. [PMID: 193497 DOI: 10.1016/0006-291x(77)91526-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
22
|
|
23
|
Maldonado JM, Herrera J, Paneque A, Losada M. Reversible inactivation by NADH and ADP on Chlorella fusca nitrate reductase. Biochem Biophys Res Commun 1973; 51:27-33. [PMID: 4349325 DOI: 10.1016/0006-291x(73)90502-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
24
|
Losada M, Herrera J, Maldonado J, Paneque A. Mechanism of nitrate reductase reversible inactivation by ammonia in Chlamydomonas. ACTA ACUST UNITED AC 1973. [DOI: 10.1016/0304-4211(73)90017-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
25
|
Herrera J, Paneque A, Maldonado JM, Barea JL, Losada M. Regulation by ammonia of nitrate reductase synthesis and activity in Chlamydomonas reinhardi. Biochem Biophys Res Commun 1972; 48:996-1003. [PMID: 4404625 DOI: 10.1016/0006-291x(72)90707-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
26
|
Cárdenas J, Rivas J, Paneque A, Losada M. Effect of iron supply on the activities of the nitrate-reducing system from Chlorella. Arch Mikrobiol 1972; 81:260-3. [PMID: 5012156 DOI: 10.1007/bf00412244] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
27
|
Guerrero MG, Rivas J, Paneque A, Losada M. Mechanism of nitrate and nitrate reduction in Chlorella cells grown in the dark. Biochem Biophys Res Commun 1971; 45:82-9. [PMID: 4400858 DOI: 10.1016/0006-291x(71)90053-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
28
|
Affiliation(s)
- A M. Relimpio
- Departamento de Bioquimica, Facultad de Ciencias y CSIC. Universidad de Sevilla, Sevilla, Spain
| | | | | | | |
Collapse
|
29
|
Abstract
Molybdenum is absolutely required for the nitrate-reducing activity of the nicotinamide adenine dinucleotide nitrate reductase complex isolated from Chlorella fusca. The whole enzyme nicotinamide adenine dinucleotide nitrate reductase is formed by cells grown in the absence of added molybdate, but only its first activity (nicotinamide adenine dinucleotide diaphorase) is functional. The second activity of the complex, which subsequently participates also in the enzymatic transfer of electrons from nicotinamide adenine dinucleotide to nitrate (FNH(2)-nitrate reductase), depends on the presence of molybdenum. Neither molybdate nor nitrate is required for nitrate reductase synthesis de novo, but ammonia acts as a nutritional repressor of the complete enzyme complex. Under conditions which exclude de novo synthesis of nitrate reductase, the addition of molybdate to molybdenum-deficient cells clearly increases the activity level of this enzyme, thus suggesting in vivo incorporation of the trace metal into the pre-existing inactive apoenzyme.Competition studies with tungstate corroborate these conclusions and indicate that the only role played by molybdenum in Chlorella is connected with the reduction of nitrate to nitrite. Tungsten seems to act by replacing molybdenum in the nitrate reductase complex, thus rendering inactive the FNH(2)-nitrate reductase portion of the nicotinamide adenine dinucleotide nitrate reductase complex.
Collapse
Affiliation(s)
- J M Vega
- Departmento de Bioquímica, Facultad de Ciencias y CSIC, Universidad de Sevilla, Spain
| | | | | | | | | |
Collapse
|
30
|
|
31
|
Affiliation(s)
- W G. Zumft
- Instituto de Biología Celular, CSIC, Facultad de Ciencias, Universidad de Sevilla, Spain
| | | | | | | |
Collapse
|
32
|
Losada M, Paneque A, Aparicio PJ, Vega JM, Cárdenas J, Herrera J. Inactivation and repression by ammonium of the nitrate reducing system in chlorella. Biochem Biophys Res Commun 1970; 38:1009-15. [PMID: 4314387 DOI: 10.1016/0006-291x(70)90340-2] [Citation(s) in RCA: 132] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
33
|
|
34
|
Affiliation(s)
- A Paneque
- Instituto de Biología Celular, C.S.I.C., y Facultad de Ciencias, Universidad de Sevilla, Spain
| | | | | | | | | |
Collapse
|
35
|
|
36
|
|
37
|
|
38
|
|
39
|
|
40
|
Losada M, Ramírez JM, Paneque A, Del Campo FF. Light and dark reduction of nitrate in a reconstituted chloroplast system. Biochim Biophys Acta 1965; 109:86-96. [PMID: 4379419 DOI: 10.1016/0926-6585(65)90093-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
41
|
|
42
|
|