scholarly journals Reduced nicotinamide–adenine dinucleotide–nitrite reductase from Azotobacter chroococcum

1973 ◽  
Vol 133 (4) ◽  
pp. 701-708 ◽  
Author(s):  
J. M. Vega ◽  
M. G. Guerrero ◽  
E. Leadbetter ◽  
M. Losada
Keyword(s):  
Nitrogen Source ◽  
Nitrite Reductase ◽  
Nicotinamide Adenine Dinucleotide ◽  
Culture Media ◽  
Reductase Activity ◽  
Direct Reduction ◽  
Azotobacter Chroococcum ◽  
Soluble Form ◽  
Reduced Nicotinamide Adenine Dinucleotide

1. The assimilatory nitrite reductase of the N2-fixing bacterium Azotobacter chroococcum was prepared in a soluble form from cells grown aerobically with nitrate as the nitrogen source, and some of its properties have been studied. 2. The enzyme is a FAD-dependent metalloprotein (mol.wt. about 67000), which stoicheiometrically catalyses the direct reduction of nitrite to NH3 with NADH as the electron donor. 3. NADH–nitrite reductase can exist in two either active or inactive interconvertible forms. Inactivation in vitro can be achieved by preincubation with NADH. Nitrite can specifically protect the enzyme against this inactivation and reverse the process once it has occurred. 4. A. chroococcum nitrite reductase is an adaptive enzyme whose formation depends on the presence of either nitrate or nitrite in the nutrient solution. 5. Tungstate inhibits growth of the microorganism very efficiently, by competition with molybdate, when nitrate is the nitrogen source, but does not interfere when nitrite or NH3 is substituted for nitrate. The addition of tungstate to the culture media results in the loss of nitrate reductase activity but does not affect nitrite reductase.

Effects of 2,4-D and Amino Acids on Field Bindweed in Vitro

Weed Science ◽  
1973 ◽  
Vol 21 (2) ◽  
pp. 135-138 ◽  
Author(s):  
R. G. Harvey ◽  
T. J. Muzik
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Culture Media ◽  
Reductase Activity ◽  
Convolvulus Arvensis ◽  
Field Bindweed ◽  
Agar Media ◽  
Differential Binding ◽  
Dichlorophenoxy Acetic Acid

Two clones of field bindweed (Convolvulus arvensisL.) which differed in their susceptibility to (2,4-dichlorophenoxy)acetic acid (2,4-D) under field and greenhouse conditions also exhibited similar differences when stem cells were cultured in liquid and agar media. Amino acids added to the culture media altered the response to 2,4-D. Glutamic acid increased the tolerance of the susceptible (S) clone, but reduced the tolerance of the resistant (R) clone. Glutamine increased the susceptibility of the S clone to a much greater degree than it did the R clone. No significant differences were noted in the rates of absorption of metabolism of 2,4-D by the two clones. Glutamine increased and glutamic acid decreased 2,4-D absorption by both clones. Levels of nitrate reductase activity (NRA), soluble protein (SP), and gross RNA (GR) increased in the S tissues but decreased or remained constant in the R tissues exposed to 4.5 × 10−5M 2,4-D. Correlations between 2,4-D susceptibility and NRA demonstrated a relationship between the effects of 2,4-D and nitrogen metabolism. Differential binding of 2,4-D within the cells appears to be the most likely explanation for the differences in response to 2,4-D.

scholarly journals Deiodination of l-thyroxine and its activity on the oxidation in vitro of reduced nicotinamide–adenine dinucleotide by peroxidase plus hydrogen peroxide

1971 ◽  
Vol 125 (3) ◽  
pp. 869-878 ◽  
Author(s):  
Trinidad Jolin ◽  
Gabriella Morreale De Escobar
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Alternative Explanation ◽  
Diphenyl Ether ◽  
Reaction Medium ◽  
Nadh Oxidation ◽  
Phenolic Ring ◽  
Active Moiety ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Competing Reactions

When l-thyroxine activates the oxidation of NADH by peroxidase+H2O2, little removal of phenolic-ring iodine atoms becomes apparent until most of the NADH has been oxidized, after which it increases markedly. This extensive deiodination is accompanied by loss of the ability of thyroxine to catalyse the oxidation of NADH by peroxidase+H2O2. The slight deiodination observed before the appearance of extensive deiodination is somewhat higher when the effect of thyroxine on NADH oxidation is greater, and lower when thyroxine has exerted a slighter effect. ICN (but not I2 or thyronine) catalyses NADH oxidation, in both the presence and the absence of peroxidase+H2O2: thyroxine+peroxidase+H2O2 are thus comparable with ICN alone in their effects on NADH oxidation. The obvious conclusion from the above observation, namely that the active moiety is the halogen liberated from thyroxine (or ICN) is, however, not directly supported by some of the results obtained by measuring the degree of deiodination of thyroxine in the system. In an attempt to reconcile some apparently contradictory conclusions, it is suggested that, when thyroxine activates oxidation of NADH by peroxidase+H2O2, the diphenyl ether structure is undergoing cyclic deiodination and iodination. This would be accompanied by the maintenance in the reaction medium of an oxidized form of iodine, similar to that liberated by ICN, which would be the actual active moiety, until the NADH concentration becomes so low that the diphenyl ether structure is ruptured oxidatively. An alternative explanation is that thyroxine is oxidized to a form that either oxidizes NADH or loses iodine in competing reactions.

NAD(P)H oxidase–dependent platelet superoxide anion release increases platelet recruitment

Blood ◽  
2002 ◽  
Vol 100 (3) ◽  
pp. 917-924 ◽  
Author(s):  
Florian Krötz ◽  
Hae Young Sohn ◽  
Torsten Gloe ◽  
Stefan Zahler ◽  
Tobias Riexinger ◽  
...  
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Thrombus Formation ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Human Platelets ◽  
Nicotinamide Adenine ◽  
Irreversible Aggregation ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Specific Peptide

Abstract Platelets, although not phagocytotic, have been suggested to release O2−. Since O2−-producing reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) oxidases can be specifically activated by certain agonists and are found in several nonphagocytotic tissues, we investigated whether such an enzyme is the source of platelet-derived O2−. We further studied which agonists cause platelet O2−release and whether platelet-derived O2− influences thrombus formation in vitro. Collagen, but not adenosine 5′-diphosphate (ADP) or thrombin, increased O2− formation in washed human platelets. This was a reduced nicotinamide adenine dinucleotide (NADH)–dependent process, as shown in platelet lysates. Consistent with a role of a platelet, NAD(P)H oxidase expression of its subunits p47phox and p67phoxand inhibition of platelet O2− formation by diphenylene-iodoniumchloride (DPI) and by the specific peptide-antagonist gp91ds-tat were observed. Whereas platelet-derived O2− did not influence initial aggregation, platelet recruitment to a preformed thrombus following collagen stimulation was significantly attenuated by superoxide dismutase (SOD) or DPI. It was also inhibited when ADP released during aggregation was cleaved by the ectonucleotidase apyrase. ADP in supernatants of collagen-activated platelets was decreased in the presence of SOD, resulting in lower ADP concentrations available for recruitment of further platelets. Exogenous O2−increased ADP- concentrations in supernatants of collagen-stimulated platelets and induced irreversible aggregation when platelets were stimulated with otherwise subthreshold concentrations of ADP. These results strongly suggest that collagen activation induces NAD(P)H oxidase–dependent O2− release in platelets, which in turn enhances availability of released ADP, resulting in increased platelet recruitment.

scholarly journals Impaired erythrocyte methemoglobin reduction in sickle cell disease: dependence of methemoglobin reduction on reduced nicotinamide adenine dinucleotide content

Blood ◽  
1990 ◽  
Vol 76 (5) ◽  
pp. 1008-1014
Author(s):  
CR Zerez ◽  
NA Lachant ◽  
KR Tanaka
Keyword(s):  
Reductase Activity ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
Cell Disease ◽  
Cell Age ◽  
Oxidant Damage ◽  
New Strategy ◽  
Reduced Nicotinamide Adenine Dinucleotide

We have examined aspects of methemoglobin (metHb) reduction in sickle and in thalassemic red blood cells (RBCs). NADH metHb reductase activity in sickle and thalassemic RBCs was significantly increased compared with normal RBCs. Because in vitro enzyme activity does not necessarily represent in vivo activity, we measured the rate of metHb reduction in intact RBCs. Intact thalassemic RBCs demonstrated a significantly increased rate of metHb reduction compared with normal RBCs. In contrast, intact sickle RBCs had a rate of metHb reduction that was similar to normal RBCs and significantly decreased relative to high reticulocyte RBCs of equivalent cell age. To determine the mechanism for the relative impairment of metHb reduction in sickle RBCs, we measured intraerythrocytic NADH, a cofactor in the metHb reduction reaction. Thalassemic RBCs had a significantly increased NADH content relative to normal RBCs. In contrast, sickle RBCs did not have an increase in NADH content. Furthermore, incubating normal RBCs under conditions that increase the NADH content resulted in an increased rate of metHb reduction. In contrast, conditions that decrease the NADH content in normal RBC resulted in a decreased rate of metHb reduction. These data and other results suggest that metHb reduction in intact RBCs is dependent on NADH content, and that the impaired metHb reduction rate in sickle RBCs may be a result of a lack of increase in NADH content. The dependence of metHb reduction on RBC NADH content and the ability to manipulate NADH content in vitro suggest a new strategy for decreasing oxidant damage to sickle RBCs in vivo.

scholarly journals HISTOCHEMICAL DEMONSTRATION OF THE SOLUBLE ENZYME, KETOSE REDUCTASE (SORBITOL DEHYDROGENASE), BY UTILIZING A NEW FIXING SOLUTION

1965 ◽  
Vol 13 (7) ◽  
pp. 583-594 ◽  
Author(s):  
ANNE B. JOHNSON
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Reaction Rate ◽  
Ganglion Cells ◽  
Reductase Activity ◽  
Histochemical Demonstration ◽  
Nicotinamide Adenine ◽  
Soluble Enzyme ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Parenchymal Cells ◽  
Coagulating Gland

Localization of the activity of the soluble enzyme, ketose reductase, was made possible by using a high-tonicity fixative containing formalin, ethanol, and tris (hydroxymethyl)aminomethane and by maintaining high tonicity in the incubating medium. Incubations could be performed at pH 8.8, an optimal pH for the conversion of sorbitol to fructose. False localization, probably resulting from diffusion of the first reactions product, reduced nicotinamide adenine dinucleotide, was minimized by slowing the reaction rate and using less tissue in the incubating medium. When this medium was tested with phenazine methosulfate, neither reduced nicotinamide adenine dinucleotide nor soluble dehydrogenase activity was detected. Ketose reductase activity was demonstrable throughout the epithelia of the seminal vesicle and the coagulating gland of the mouse. The activity was greater in the coagulating gland. It also was present in spermatozoa, central hepatic parenchymal cells, and renal proximal tubule. It was not present in the vas deferens epithelium nor ganglion cells. Reactivity in smooth muscle was believed to be artifact.

scholarly journals DETERMINATION OF GLUTATHIONE REDUCTASE ACTIVITY IN MICROGRAM SAMPLES OF TISSUE, QUANTITATIVE HISTOLOGIC DISTRIBUTION OF THE ENZYME IN THE RAT ADRENAL AND EFFECT OF ADRENOCORTICOTROPIN

1968 ◽  
Vol 16 (3) ◽  
pp. 185-190 ◽  
Author(s):  
NORBERTO A. SCHOR ◽  
DAVID GLICK
Keyword(s):  
Glutathione Reductase ◽  
Nicotinamide Adenine Dinucleotide ◽  
Reductase Activity ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Border Region ◽  
Nicotinamide Adenine ◽  
Subcutaneous Injections ◽  
Glutathione Reductase Activity ◽  
Reduced Nicotinamide Adenine Dinucleotide

A fluorometric method for determination of glutathione reductase activity in microgram samples of tissue, i.e., microtome sections, based on measurement of the decrease of reduced nicotinamide adenine dinucleotide phosphate due to its oxidation on reaction with oxidized glutathione, was developed and applied to the quantitative histologic distribution of the enzyme in the adrenal gland of the rat. Single subcutaneous injections of adrenocorticotropin in saline solution (25 mg/kg) produced little change of enzyme activity in any of the histologic zones, although there was some tendency for the peak activity to shift from fasciculata to the fascicular-reticular border region. The possible interrelationship of glutathione reductase with ascorbic acid and reduced nicotinamide adenine dinucleotide phosphate in adrenal function was considered.

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