Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Washed microsomes from rabbit liver reduced 1-nitrosoadamantane to N-hydroxy-1-aminoadamantane in the presence of a cofactor solution under aerobic conditions; no further reduction of the hydroxylamino metabolite to 1-aminoadamantane (amantadine) occurred. Reduced pyridine nucleotide cofactors are needed for the metabolic reduction. The rate of formation of N-hydroxy-1-aminoadamantane depended upon the microsomal protein content, the time of incubation and the concentration of 1-nitrosoadamantane incubated. The metabolic reduction occurred in air as well as under nitrogen or carbon monoxide. Cupric chloride, mercuric chloride, cysteamine, FAD, and FMN decreased significantly the C-nitroso reductase. The properties of the C-nitroso reductase differed from those of other microsomal reductive pathways.
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PMID:Metabolic reduction of 1-nitrosoadamantane by rabbit liver microsomes. Properties of a C-nitroso reductase system. 3 89

Carbon monoxide inhibited the carbon tetrachloride-induced NADPH oxidation rate. The addition of methylviologen to the incubation mixture under the atmosphere of nitrogen resulted in the enhancement of the reductase activity of microsomes for carbon tetrachloride, as determined by chloroform formation. The addition of methylviologen also enhanced the carbon tetrachloride-induced loss of cytochrome P-450, while the apparent content of cytochrome b5 and the activity of NADPH-cytochrome c reductase remained unchanged. Under a strong inhibition of lipid peroxidation by addition of EDTA, carbon tetrachloride induced a clear loss of cytochrome P-450 to the extent similar to that seen in the absence of EDTA. These results indicate that cytochrome P-450 is directly degraded in association with the reductive metabolism of carbon tetrachloride by cytochrome P-450.
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PMID:The apparent loss of cytochrome P-450 associated with metabolic activation of carbon tetrachloride. 4 18

In combination with the Mo-Fe protein of nitrogenase from Klebsiella pneumoniae, the Fe protein of nitrogenase from Clostridium pasteurianum forms an active enzyme with novel properties different from those of either of the homologous nitrogenases. The steady-state rates of reduction of acetylene and H+ are 12% of those of the homologous system from C.pasteurianim. Acetylene reductase activity exhibited an approx. 10min lag at 30 degrees C before the rate of reduction became linear, consistent with a once-only activation step being necessary for acetylene reduction to occur. No such lag was observed for H2 evolution. The activity with N2 as a reducible substrate was very low, implying that acetylene reductase activity is not necessarily an accurate indication of nitrogen-fixing ability. This is of particular relevance to studies on mutant and agronomically important organisms. Stopped-flow spectrophotometric studies showed unimolecular electron transfer from the Fe protein to the Mo-Fe protein to occur at the same rate (k2 = 2.5 X 10(2)s-1) and with the same dependence on ATP concentration (apparent KD = 400 muM) as with the homologous Klebsiella nitrogenase. However, an ATP/2e ratio of 50 was obtained for H2 evolution, indicating that ATP hydrolysis had been uncoupled from electron transfer to substrate. These data indicate that ATP has at least two roles in the mechanism of nitrogenase action. The combination of the Mo-Fe protein of nitrogenase of C.pasteurianim and the Fe protein of K.pneumoniae were inactive in all the above reactions, except for a weak adenosine triphosphatase activity, 0.5% of that of the homologous K.pneumoniae system.
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PMID:Nitrogenases from Klebsiella pneumoniae and Clostridium pasteurianum. Kinetic investigations of cross-reactions as a probe of the enzyme mechanism. 13

Young mycelia of the fungus Neurospora crassa contain a soluble NADH-linked sideramine reductase, which may be responsible for liberating iron in vivo from accumulated sideramines during iron-deficient cultivation. The enzymes can be assayed using a soluble supernatant fraction, EDTA, and an atmosphere of pure nitrogen. The enzyme is stable without loss of activity up to 45 degrees C and has an optimum of activity at pH 7.0. Besides coprogen (Km = 100 micrometer, V=2.8 nmol/min per mg protein), some other ferrichrome-type compounds are reduced. However, ferrichrome, ferrirubin coprogen B and ferrioxamine are poor substrates. When the mucelia were grown in a medium containing 10(-5) M ferri iron, the activity of the reductase was found to be only 30% of that found under low iron conditions. The enzyme is inhibited by oxygen, SH-alkylating agents and partly by some detergents. Unlike the reductase of N. crassa, the corresponding enzyme from Aspergillus fumigatus revealed low reduction of coprogen and high reduction of ferrichrome, indicating genusdependent specificities of sideramine reduction enzymes in fungi. The participation of acids of the citric acid cycle as natural iron acceptors during strong iron deficiency is studied and confirmed by iron uptake measurements on isolated mitochondria.
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PMID:Enzymatic release of iron from sideramines in fungi. NADH:sideramine oxidoreductase in Neurospora crassa. 14 35

Male guinea pigs were exposed to nitrogen dioxide (2 mg/m3) during 180 days (8 hours a day). Long-term exposure induced thickening of the corneal layer of the epidermis as well as inflammatory infiltrations in the proper skin. The following enzymes were estimated histochemically in skin samples of experimental and control animals: succinic dehydrogenase, NADH2-tetrazolium reductase, lactate dehydrogenase; alkaline phosphatase, acid phosphatase and adenosine triphosphatase. Chronic exposrue stimulated a decrease of NADH2-tetrazolium reductase in the epidermis and connective tissue components of proper skin and marked positive reaction of lactate dehydrogenase in epidermal cells and hair follicles. Increase of a diffuse reaction on adenosine triphosphatase in smooth muscles of the skin was found also in exposed animals.
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PMID:Histopathological and histochemical studies of the skin of guinea pigs after long-term exposure to nitrogen dioxide. 14 74

Growing cultures of several strains of Pseudomonas fluorescens and Pseudomonas chlororaphis produced N2O as the only detectable gaseous product of denitrification, and other strains produced N2 as the gaseous end product of denitrification. All of the nitrogen in NO3- or NO2- added to cell suspensions of the N2O-producing strains P. fluorescens PJ 185 and P. chlororaphis B-560 was recovered as N2O. All of the nitrogen in NO3- or NO2- added to cell suspensions of the N2-producing strain P. fluorescens PJ70 was converted to N2. Cell extracts of P. fluorescens PJ 70, PJ 185, and P. chlororaphis B-560 exhibited NO3- reductase activity when sodium succinate was the electron donor. Reduced nicotinamide adenine dinucleotide and flavine adenine dinucleotide were required to demonstrate NO2- reductase activity in cell extracts.
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PMID:Nitrous oxide as end product of denitrification by strains of fluorescent pseudomonads. 19 99

Coalpha-[alpha-(Aden-9-yl)]-Cobeta-adenosylcobamide (pseudocoenzyme B12) purified from Clostridium tetanomorphum has been reacted with ribonucleotide reductase purified from Lactobacillus leichmannii under various conditions, and the properties of the products obtained have been compared by electron paramagnetic resonance (EPR) with those previously reported for products formed from the normal coenzyme (adenosylcobalamin). The rapidly formed intermediate and the slowly formed "doublet" species from the pseudocoenzyme have EPR spectra identical with those formed from the normal coenzyme. This and other considerations make it less likely that the unusual magnetic properties of the rapidly formed intermediate are due to strongly distorted octahedral symmetry about Co(II) as previously postulated. Instead it is probable that the EPR spectrum is due to interaction of the radical pair by both exchange coupling and magnetic dipole--dipole coupling. Although Coalpha-[alpha-(aden-9-YL)]cob(II)amide in solution does not show superhyperfine splitting in the EPR spectrum because of its base-off configuration, the cob(II)amide formed by degradation of the pseudocoenzyme within the catalytic site of the enzyme did show triplets due to a nitrogen axially coordinated to cobalt. This suggests that binding of the cob(II)amide to the reductase catalytic site causes a shift to the base-on form.
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PMID:Mechanism of Lactobacillus leichmannii ribonucleotide reductase studied with Coalpha-[alpha-(Aden-9-yl)]-Cobeta-adenosylcobamide (Pseudocoenzyme B12) as coenzyme. 22 Oct 6

The purification procedure and properties of metlegoglobin reductase from the soluble fraction of lupine (Lupinus luteus L.) nodules and from the proteins secreted by bacteroids Rhizobium lupini in vitro are described. The properties of both forms of enzyme were found to be similar. A metlegoglobin reductase preparation purified 125-fold with a yield of 21% was obtained. The enzyme is strictly specific to the cofactor (NADH). No substrate specificity was revealed. The enzyme reduces oxidized cytochrome c, Mb+, Lb+, Hb+ and exygen. The pH optimum for the enzyme is 7,4. The enzyme is inhibited by p-chloromercurybenzoate. In some properties the enzyme from lupine nodules is close to methemoglobin reductase from the erythrocytes. It was shown that apart from metlegoglobin reductase, bacteroids secrete some other proteins, which is indicative of a close interrelationship between the bacteroids and the plant in a symbiotic nitrogen-fixing system.
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PMID:[Metlegoglobin reductase from lupine nodules. Purification and properties]. 22 83

Cells of Proteus mirabilis could oxidize L-phenylalanine to phenylpyruvate only when grown in the presence of a number of amino acids, particularly, L-alanine, L-asparagine, L-glutamate, and L-glutamine. Production of phenylalanine oxidase was slowly lost upon growth in a minimal medium containing ammonium ions as a nitrogen source but was reversed by the addition of casein hydrolysate. Oxidase activity as well as a phenylalanine-dichlorophenolindophenol (DCIP) reductase activity increased in P. mirabilis only during cell multiplication. Both rifampin and nalidixic acid caused inhibition of oxidase synthesis. A phenylalanine-active transport was found to be operative when bacteria were grown in the absence of added amino acids. After anaerobic growth, cells of P. mirabilis had lost their ability to carry the phenylalanine oxidase reaction when assayed in the presence of air, and nitrate could not be used as an electron acceptor for the oxidation of phenylalanine. However, some phenylalanine-dichlorophenolindophenol reductase activity was still present in anaerobic bacteria at the early stage of cell multiplication.
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PMID:Regulation of phenylalanine oxidase synthesis in Proteus mirabilis. 36 13

At growth temperatures above 37 degrees C, Klebsiella pneumoniae does not grow in a medium containing N2 or NO3- as nitrogen sources. However, both the growth in the presence of other nitrogen sources as well as the in vitro nitrogenase activity are not affected at this temperature. The inability to fix N2 at high temperature is due to the failure of the cells to synthesize nitrogenase and other nitrogen fixation (nif) gene encoded proteins. When cells grown under nitrogen fixing conditions at 30 degrees C were shifted to 39 degrees C, there was a rapid decrease of the rate of de novo biosynthesis of nitrogenase (component 1), nitrogenase reductase (component 2), and the nifJ gene product. There was no degradation of nitrogenase at the elevated temperature since preformed enzyme remained stable over a period of at least 3 h at 39 degrees C. Thus, temperature seems to represent a third control system, besides NH4+ and O2, governing the expression of nif genes of K. pneumoniae.
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PMID:Temperature control of nitrogen fixation in Klebsiella pneumoniae. 39 99


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