[44] Nitrite reductase

Losada, M.; Paneque, A.

doi:10.1016/s0076-6879(71)23120-7

Cited by 85 publications

(38 citation statements)

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“…Published assays were used for NR (21), glutamate dehydrogenase (31), glycolate oxidase (29), NAD-malate dehydrogenase (29), NAD-lactate dehydrogenase (15), a-glycerol phosphate dehydrogenase (4), acid phosphatase (14), and xanthine oxidase (23). fi-Benzoyl-DL-arginine-p-nitroanilide from Sigma was hydrolyzed by Kruger's procedure (16) and L-leucine-p-nitroanilide by the method of Beevers (1).…”

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confidence: 99%

NADH-Nitrate Reductase Inhibitor from Soybean Leaves

Jolly

Tolbert²

1978

Plant Physiol.

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A NADH-nitrate reductase inhibitor has been isolated from young soybean (Glycine max L. Meff. Var. Amsoy) leaves that had been in the dark for 54 hours. The presence of the inhibitor was first suggested by the absence of nitrate reductase activity in the homogenate until the inhibitor was removed by diethylaminoethyl (DEAE)-cellulose chromatography. The inhibitor inactivated the enzyme in homogenates of leaves harvested in the light. Nitrate reductases in single whole cells isolated through a sucrose gradient were equally active from leaves grown in light or darkness, but were inhibited by addition of the active inhibitor.The NADH-nitrate reductase inhibitor was purified 2,500-fold to an electrophoretic homogeneous protein by a procedure involving DEAEcellulose chromatography, Sephadex G-100 filtration, and ammonium sulfate precipitation foUowed by dialysis. The assay was based on nitrate reductase inhibition. A rapid partial Isolation procedure was also developed to separate nitrate reductase from the inhibitor by DEAE-cellulose chromatography and elution with KNO3. The inhibitor was a heat-labile protein of about 31,000 molecular weight with two identical subunits. After electrophoresis on polyacrylamide gel two adjacent bands of protein were present; an active form and an inactive form that developed on standing. The active factor inhibited leaf NADH-nitrate reductase but not NADPHnitrate reductase, the bacterial nitrate reductase or other enzymes tested.The site of inhibition was probably at the reduced flavin adenine dinucleotide-NR reaction, since it did not block the partial reaction of NADHcytochrome c reductase. The hibitor did not appear to be a protease. Some form of association of the active hibitor with nitrate reductase was indicated-by a change of inhibitor mobility through Sephadex G-75 In the presence of the enzyme. The Inhibition of nitrate reductase was noncompetitive with nitrate but caused a decrease in V,,.The Isolated Inhibitor was inactivated in the light, but after 24 hours in the dark full inhibitory activity retrned. Equal amounts of inhibitor were present In leaves harvested from light or darkness, except that the inhibitor was at first inactive when rapidly isolated from leaves in light. Photoinactivation of yellow impure inhibitor required no additional components, but inactivation of the puri colorless inhibitor required the addition of flavin.Preliminary evidence and a procedure are given for partial isolation of a component by DEAE-cellulose chromatography that stimulated nitrate reductase. The data suggest that light-dark changes in nitrate reductase activity are regulated by specific protein inhibitors and stimulators. sively reviewed (2), and our manuscript is concerned with the discovery, isolation, and partial characterization of an inhibitory protein for NR which may account for part of these phenomena. In addition, preliminary evidence is also presented for the presence of a stimulatory protein for NR. Contrary to previous hypotheses involving a rapid loss of NR in...

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confidence: 99%

NADH-Nitrate Reductase Inhibitor from Soybean Leaves

Jolly

Tolbert²

1978

Plant Physiol.

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“…Precipitation with acetone, extraction of the protein precipitate, dialysis of the extract and removal of ferredoxin by adsorption on DEAE-cellulose were carried out according to Ramirez et al [3,8]. Adsorption of the enzyme on a DEAE-cellulose bed and its elution were also carried out according to the same authors.…”

Section: Methodsmentioning

confidence: 99%

“…Nitrite reductase was assayed with methyl viologen chemically reduced by Naz Sz 04 according to Ramirez et al [3,8]. Protein was determined by the method of Lowry et al [ 141. One enzyme unit is defined here as one micromole of nitrite disappeared per minute.…”

Section: Methodsmentioning

confidence: 99%

Purification and properties of nitrite reductase from spinach leaves

et al. 1972

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“…Homogenate was centrifuged (30 000 g for 15 min at 4 °C) and supernatant was assayed for NR and NiR activities as described respectively by Wray & Filner (1970) and Losada & Paneque (1971).…”

Section: Enzymatic Assaysmentioning

confidence: 99%

Growth and nitrate assimilation in tomato (Solanum lycopersicon)grown with different nitrogen source and treated with cadmium

Nasraoui-Hajaji¹,

Chaffei-Haouari²,

Ghorbel³

et al. 2011

Acta Botanica Gallica

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Abstract.-In tomato seedlings, the effects of Cd on growth and activity of enzymes involved in nitrate assimilation were studied on different nitrogen sources. After one week on basal growth medium, seedlings were transferred and grown for 14 days on a medium containing 5 mM nitrate, 5 mM ammonium or varying ratios of nitrate to ammonium. In each nitrogen medium, plants were divided into control and Cd treated. In nitrate-rich medium, plant dry weigh was improved while growth was more inhibited by Cd stress than in ammonium-rich medium. Regardless of nitrogen source, Cd treatments decreased nitrate contents in leaves and roots. Nitrate reductase and nitrite reductase activities were decreased by presence of ammonium in culture medium. Cd treatments inhibited NR and NiR activities independently of nitrogen form and plant organ. It could be concluded that tomato plants preferred nitrate as a nitrogen source where as external ammonium was found to inhibit growth. The addition of ammonium in nutrient solution slows down Cd absorption. Endogenous nitrate accumulation may mirror an important role of this metabolite in nitrate and nitrite reductase induction.Key words : tomato -cadmium -nitrate -ammonium -nitrate reductase -nitrite reductase.Résumé.-Chez des jeunes plantes de tomate, les effets de cadmium sur la croissance et l'activité des enzymes impliquées dans l'assimilation du nitrate ont été étu-diés en présence de différentes sources d'azote. Après une semaine sur milieu nutritif de base, les plants ont été transférés et cultivés pendant 14 jours sur un milieu contenant 5 mM de nitrate, 5 mM d'ammonium ou différentes proportions de nitrate et d'ammonium. Dans chaque milieu, les plantes ont été divisées en deux lots : témoins et traitées par Cd. Sur milieu riche en nitrate, la matière sèche des plantes a été plus importante, tandis que la croissance a été plus inhibée par le stress de Cd que sur milieu riche en ammonium. Indépendamment de la source d'azote, le traitement par Cd a diminué le contenu de nitrate dans les feuilles et les racines. Les activités nitrate réductase et nitrite réductase sont diminuées par la présence de l'ammonium dans le milieu de culture. Indépendamment de le forme d'azote et l'organe de la plante étudié, Cd inhibe les activités NR et NiR. On pourrait conclure que les plantes de tomate préfèrent le nitrate comme source d'azote, alors que l'ammonium exogène inhibe la croissance. L'accumulation endogène du nitrate peut reflé-ter le rôle important de ce métabolite dans l'induction de la nitrate et nitrite réductases.Mots clés : tomate -cadmium -nitrate -ammonium -nitrate réductase -nitrite réductase.

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[44] Nitrite reductase

Cited by 85 publications

References 10 publications

NADH-Nitrate Reductase Inhibitor from Soybean Leaves

NADH-Nitrate Reductase Inhibitor from Soybean Leaves

Purification and properties of nitrite reductase from spinach leaves

Growth and nitrate assimilation in tomato (Solanum lycopersicon)grown with different nitrogen source and treated with cadmium

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