Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.99.3 (diaphorase)
5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cell-free ammonia-oxidizing system of Nitrosomonas europaea was resolved into three major fractions: a membrane fraction containing cytochrome a1 and c-type cytochromes, a fraction with hydroxylamine-cytochrome c reductase and a cytochrome c fraction. The ammonia-oxidizing activity was reconstituted by the combination of these three fractions. The activity was more consistently reconstituted by adding Nitrosomonas cytochrome c554 to the membrane fraction. The hydroxylamine-cytochrome c reductase activity of the membrane fraction increased with the addition of cytochrome c554, but the oxidation of hydroxylamine to nitrite required a further addition of cytochrome c552. The ammonia oxidation by the membrane plus cytochrome c554 was affected by the concentration of phosphate and the addition of bovine serum albumin, spermine, or MgCl2.
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PMID:A partial resolution and reconstitution of the ammonia-oxidizing system of Nitrosomonas europaea: role of cytochrome c554. 627 64

Copper Fenton systems (Cu(II)/H2O2 and Cu(II)/Asc) inactivated the lipoamide reductase and enhanced the diaphorase activity of pig-heart lipoamide dehydrogenase (LADH). Cupric ions alone were less effective. As a result of Cu(II)/H2O2 treatment, the number of titrated thiols in LADH decreased from 6 to 1 per subunit. NADH and ADP (not NAD+ or ATP) enhanced LADH inactivation by Cu(II). NADH also enhanced the effect of Cu(II)/H2O2. Dihydrolipoamide, dihydrolipoic acid, Captopril, acetylcysteine, EDTA, DETAPAC, histidine, bathocuproine, GSSG and trypanothione prevented LADH inactivation. 100 microM GSH, DL-dithiothreitol, N-(2-mercaptopropionylglicine) and penicillamine protected LADH against Cu(II)/Asc and Cu(II), whereas 1.0 mm GSH and DL-dithiothreitol also protected LADH against Cu(II)/H2O2. Allopurinol provided partial protection against Cu(II)/H2O2. Ethanol, mannitol, Na benzoate and superoxide dismutase failed to prevent LADH inactivation by Cu(II)/H2O2 or Cu(II). Catalase (native or denaturated) and bovine serum albumin protected LADH but that protection should be due to Cu binding. LADH inhibited deoxyribose oxidation and benzoate hydroxylation by Cu(II)/H2O2. It is concluded that site-specifically generated HO, radicals were responsible for LADH inactivation by Cu(II) Fenton systems. The latter effect is discussed in the context of ischemia-reoxygenation myocardial injury.
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PMID:Inactivation of heart dihydrolipoamide dehydrogenase by copper Fenton systems. Effect of thiol compounds and metal chelators. 775

Trypanosoma brucei S427cl1 organisms made 6 divisions in modified minimal essential medium (BMEM) supplemented with fetal bovine serum (FBS)-low or high density lipoprotein (LDL, HDL) and fatty acid-free bovine serum albumin (FAF-BSA). Omission of lipoproteins or FAF-BSA from the medium caused the parasites to accumulate in G1 of the cell cycle and to lose the ability to replicate at 37 degrees C. Proteinase K-treated LDL or HDL, which did not have detectable apolipoprotein, supported the G1 to S cell cycle transition of T. brucei S427cl1 organisms in BMEM supplemented with FAF-BSA. Addition of C6:0, C7:0 or fatty C8:0 fatty acid (1 mol fatty acid mol-1 FAF-BSA in the incubation mixture) to serum-free medium supplemented with LDL or HDL and FAF-BSA prevented T. brucei S427cl1 organisms from progressing through G1 into S of the cell cycle. T. brucei S427cl1 organisms became stumpy-like forms during plateau phase growth under axenic conditions. Stumpy-like T. brucei S427cl1 organisms were mainly in G1 of the cell cycle, expressed raised levels of NAD diaphorase activity, were unable to replicate at 37 degrees C, but were able to differentiate to replicating procyclic organisms. Medium collected from plateau phase cultures of T. brucei S427cl1 did not support the G1 to S cell cycle transition of exponentially growing T. brucei organisms. The capacity of plateau phase medium to support G1 to S transition of T. brucei S427cl1 organisms was restored by addition of FAF-BSA and its capacity to support 4 cycles of replication of the parasites was restored by addition of FAF-BSA and LDL or HDL.
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PMID:Control of G1 to S cell cycle progression of Trypanosoma brucei S427cl1 organisms under axenic conditions. 843 15

Nitrate reductase from the yeast Candida nitratophila was found to contain one molecule of cytochrome b557 and one atom of molybdenum per subunit. FAD/haem-dependent diaphorase activity (haem domain) was associated with a 40 kDa tryptic fragment of the subunit. The 50 amino-terminal residues of this fragment were determined, and the sequence did not show significant similarity to deduced sequences of other nitrate reductases previously published. Increasing ionic strength in vitro had a stimulatory effect on enzymic activity via stimulation of the molybdenum-dependent terminal nitrate-reducing activity. Stimulation of activity by exogenous protein (bovine serum albumin or casein) also appeared to be an ionic effect. Stimulation of catalytic activity by phosphate was a separate effect.
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PMID:Further characterization of the assimilatory nitrate reductase from the yeast Candida nitratophila. 847 56

Treatment of red cell ghosts with ozone inhibited both AChE (marking the outside of the membrane) and G3PDH (marking the inside of the membrane). There was no change in tryptophan fluorescence of the ghosts after the ozone treatment. Band 3 protein was isolated from the ozone-treated ghosts. The protein was digested with trypsin to obtain water soluble peptides from the cytoplasmic N-terminal tail and the interhelical loops. Fluorescent peptides included GWVIHPLGLR from the outer loop between helices 7 and 8, and peptide WMEAAR from the N-terminal cytoplasmic tail. Neither one of these peptides was oxidized by ozone. This was true whether or not the ghosts were sealed. We conclude that the position of these tryptophans either in the membrane structure, or because of binding to other proteins in the cytoplasmic tail, protects them from oxidation by ozone. Treatment of horse heart cytochrome c with ozone did not change the absorbance spectrum in the heme region or the tryptophan absorbing region. HPLC of the ozone-treated cytochrome c showed that cytochrome c was being modified, indicated by a change in the elution time. Treatment of cytochrome c with ozone did not change the activity in the NADH-cytochrome c reductase assay. Digestion of the ozone-treated cytochrome c with trypsin gave peptides which demonstrated normal fluorescence. (Cytochrome c has abnormally low fluorescence, which is not changed by ozone exposure.) The peptides were separated by HPLC. The fluorescence of the tryptophan-containing peptide (GITWK) was not decreased by treatment of the cytochrome c by ozone. Amino acid analysis of the ozone-treated cytochrome c indicated that methionine was oxidized. We conclude that tryptophan in cytochrome c is protected from oxidation by ozone because of the interaction with the porphyrin ring. Bovine serum albumin and human serum albumin were treated with ozone. There was a monotonic decrease in tryptophan fluorescence in both cases. Digestion of BSA with trypsin produced two fluorescent peptides. The peptide FWGK was identified by coelution with the authentic peptide. The putative peptide AWSVAR was not the same as the chemically synthesized peptide. The peptide sequences FWGK and "AWSVAR" were both oxidized in ozone-treated bovine serum albumin, with no detectable discrimination. Tryptic digestion of the ozone-treated human serum albumin produced a single fluorescent peptide, which was oxidized by ozone. The putative peptide AWAVAR in the tryptic digest of HSA was distinct from chemically synthesized peptide. The oxidation of tryptophans in proteins by ozone is markedly influenced by position in tertiary structure, position in membrane structure, and by chemical interactions within the protein.
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PMID:Reaction of ozone with protein tryptophans: band III, serum albumin, and cytochrome C. 902 65

Oxygen radical generating systems, namely, Cu(II)/ H2O2, Cu(II)/ascorbate, Cu(II)/NAD(P)H, Cu(II)/ H2O2/catecholamine and Cu(II)/H2O2/SH-compounds irreversibly inhibited yeast glutathione reductase (GR) but Cu(II)/H2O2 enhanced the enzyme diaphorase activity. The time course of GR inactivation by Cu(II)/H2O2 dependent on Cu(II) and H2O2 concentrations and was relatively slow, as compared with the effect of Cu(II)/ascorbate. The fluorescence of the enzyme Tyr and Trp residues was modified as a result of oxidative damage. Copper chelators, catalase, bovine serum albumin and HO. scavengers prevented GR inactivation by Cu(II)/H2O2 and related systems. Cysteine, N-acetylcysteine, N-(2-dimercaptopropionylglycine and penicillamine enhanced the effect of Cu(II)/H2O2 in a concentration- and time-dependent manner. GSH, Captopril, dihydrolipoic acid and dithiotreitol also enhanced the Cu(II)/H2O2 effect, their actions involving the simultaneous operation of pro-oxidant and antioxidant reactions. GSSG and trypanothione disulfide effectively protected GR against Cu(II)/H2O2 inactivation. Thiol compounds prevented GR inactivation by the radical cation ABTS.+. GR inactivation by the systems assayed correlated with their capability for HO. radical generation. The role of amino acid residues at GR active site as targets for oxygen radicals is discussed.
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PMID:Inactivation of yeast glutathione reductase by Fenton systems: effect of metal chelators, catecholamines and thiol compounds. 945 90

Derivatives of benzazolo[3,2-a]quinolium salts (QSDs) are reductively activated by the enzymatic reducing agents hypoxanthine (or xanthine)/xanthine oxidase and NADH dehydrogenase as evidenced by the increase in rates of ferricytochrome c (Cyt(III)c) reduction and oxygen consumption, respectively. No correlation between Michaelis-Menten parameters and QSDs redox potentials was found regarding anaerobic or aerobic Cyt(III)c reduction, although maximum rates were observed for nitro-containing QSDs. However, oxygen consumption rates correlate with QSDs redox potentials when NADH dehydrogenase is used as reducing agent. QSDs bind covalently to bovine serum albumin (BSA) under anaerobic conditions, in the presence, and less in the absence, of HX/XO and only if the nitro group is present at the QSD. QSDs react with glutathione (GSH) in the presence of HX/XO but not in its absence, under anaerobic conditions. The amount of reacted GSH increases, and the relative amount of GSSG formed decreases, with an increase in the QSD reduction potential, thus indicating that GSH reacts with reduced nitro-containing QSDs mainly in a manner which does not involve the production of GSSG, presumably, through the formation of the nitroso-QSD-GSH conjugate. QSDs are, thus, novel nitro-containing heterocyclic compounds which could be bioreductively activated to react with oxygen and thiols.
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PMID:Reductive activation and thiol reactivity of benzazolo[3,2-a]quinolinium salts. 1514 83

The effects of decenylsuccinic acid on the swelling and respiratory capacities of mitochondria isolated from etiolated corn (Zea mays L., Wf9 x M14) shoots were studied. Decenylsuccinic acid (0.1 mM to 1.0 mM) inhibited the oxidation of succinate and malate-pyruvate, stimulated the oxidation of reduced nicotinamide adenine dinucleotide, and uncoupled phosphorylation. The swelling of isolated corn mitochondria, as determined by percentage of transmittance changes, was stimulated by decenylsuccinic acid in potassium chloride reaction media and in sucrose reaction media without bovine serum albumin. In a diaphorase (2, 6-dichlorophenolindophenol as acceptor) reaction with intact mitochondria, only the dehydrogenation rate of malate was reduced by the addition of decenylsuccinic acid. The dehydrogenation of reduced nicotinamide adenine dinucleotide or of succinate was either not affected or was stimulated depending on the diaphorase reaction medium. The oxygen uptake of mitochondria oxidizing N, N, N', N'-tetramethyl-p-phenylenediamine diHCl and ascorbate was inhibited at decenylsuccinic acid concentrations greater than 0.5 mM.The results presented lead to the hypothesis that the primary effect of decenylsuccinic acid on isolated corn mitochondria is on the physical properties of the membranes and that decenylsuccinic acid-affected stimulation or inhibition of respiration results from the physical disruption of the membrane. These results appear to be consistent with those previously reported in whole plant studies.
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PMID:Some effects of decenylsuccinic Acid on isolated corn mitochondria. 1665 57

A novel electrochemical technique for lipopolysaccharide (LPS) detection has been developed using a combination of ferrocenylboronic acid derivatives and an enzyme-modified electrode. The enzyme-modified electrode was constructed from a gold electrode modified with a bovine serum albumin membrane containing diaphorase. Ferrocenylboronic acid derivatives are oxidized on the electrode, and then regenerated by a diaphorase-catalyzed reaction in the presence of NADH. The consumption/regeneration cycle for ferrocenylboronic acid derivatives resulted in a chemically amplified current response. The current response for ferrocenylboronic acid derivatives decreased in association with its complexation with glycosyl units of LPS, and this current decrease caused by LPS was also amplified by the recycling process. On the other hand, the addition of a monosaccharide such as D-mannose or D-galactose induced no response at the same LPS concentration. The enzyme membrane immobilized on the electrode plays an important role in selectivity as well as chemical amplification. In addition, the enzyme-modified electrode exhibited a rapid response of 5 min for LPS, which is much faster than the currently used method. The detection limit of LPS from Escherichia coli O127:B8 was as low as 50 ng ml-1.
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PMID:Electrochemically amplified detection for lipopolysaccharide using ferrocenylboronic acid. 1680 89

Chemotherapy has been used on a large scale in countries where the blood fluke Schistosoma japonicum is endemic. This has led to a lower intensity of infections and consequently lower diagnostic values of commonly used diagnostic tests like serology and Kato-Katz stool smear. We designed a novel real-time PCR method for detection of S. japonicum in stool samples. Further, we evaluated different versions of an inexpensive, non-commercial extraction method, ROSE, as well as the commercial QIAamp DNA Stool Mini Kit. PCR primer sequences were designed targeting the mitochondrial NADH dehydrogenase I gene. Bovine serum albumin was added to the DNA extracts and SYBR Green was used for detection. The PCR method was evaluated with non-infected stool samples spiked with S. japonicum eggs. It demonstrated high sensitivity, even in samples containing a single egg. The two extraction methods were equally effective. The PCR was specific for S. japonicum when tested against other Schistosoma species, Trichuris trichiura, hookworm and Taenia sp. We conclude that this novel real-time PCR, in combination with either ROSE or QIAamp DNA Stool Mini Kit extraction, is a sensitive and specific tool for diagnosing S. japonicum in human stool samples.
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PMID:Novel real-time PCr for detection of Schistosoma japonicum in stool. 1712 83


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