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

---

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

This new assay procedure for diaphorase eliminates problems of high blank rates and nonlinear kinetics associated with other methods. The dye thiazolyl blue tetrazolium bromide is reduced in the presence of NADH and diaphorase to yield a colored formazan, which as maximum absorbance at 560 nm.
...
PMID:A new assay for diaphorase activity in reagent formulations, based on the reduction of thiazolyl blue. 4 50

Six different lipophilic (hydrophobic) organic cations, tetraethyl-, tetrapropyl, tetrabutyl-, tetrapentyl-, tetrahexyl-, and tetraheptylammonium bromide, depressed respiratory control in rat liver mitochondria. Evaluation of mitochondrial responses in terms of a quadratic equation in log P (an index of lipophilicity) indicated that the NADH dehydrogenase receptor site for inhibitor (diminution of control of glutamate, alpha-ketoglutarate, and beta-hydroxybutyrate respiration) was more lipophilic than receptor sites for flavin-linked substrates (reduction of control of succinate, choline and alpha-glycerophosphate respiration). The succinate dehydrogenase receptor site for inhibition by the tetraalkylammonium bromides was more hydrophillic (less lipophilic) than the choline or alpha-glycerophosphate dehydrogenase receptor sites. Depression of respiratory control may be a function of charge density and of lipophilicity at specific inner membranal sites and the susceptible site may differ for different respiratory substrates.
...
PMID:Respiratory control depression by tetraalkylammonium bromides in rat liver mitochondria. 124 57

Adult, male rats were infected with 20 metacercariae of Fasciola hepatica given orally, other rats were left untreated. Five weeks after infestation, some animals received phenobarbitone, 3-methylcholanthrene, beta-naphthoflavone or Arochlor 1254, to induce liver drug metabolizing enzymes. Fascioliasis provoked decreases in aminopyrine N-demethylase, aniline hydroxylase, the mutagenic activity of cyclophosphamide and cytochrome P-450 concentration in untreated or phenobarbitone or Arochlor pretreated rats. In contrast, cytochrome b5, NADPH cytochrome c reductase, ethyoxycoumarin O-deethylase and the enzymatic activation of ethidium bromide were not affected by fascioliasis whatever pretreatment was given. Fascioliasis decreased liver drug metabolizing enzymes which were specifically induced by both phenobarbitone and Arochlor, this could be due to either the specific action of toxic excretions of flukes or to the particular localization of tissue damage within the liver lobule.
...
PMID:Induction of drug metabolizing enzymes in the liver of rats infested with Fasciola hepatica. 286 51

Hepatocyte cytotoxicity caused by substituted benzoquinones was associated with increased cytosolic Ca2+ concentration. p-Benzoquinone-induced hepatotoxicity was enhanced when the hepatocytes were loaded with Ca2+ by preincubation with ATP. A similar order of potency of the substituted benzoquinones in releasing Ca2+ from isolated mitochondria and inducing hepatocyte cytotoxicity was found; in decreasing order, this was 2-Br-, unsubstituted-, 2-CH3-, 2,6-(CH3O)2-, 2,6-(CH3)2-, 2,5-(CH3)2-, 2,3,5-(CH3)3-, and 2,3,5,6-(CH3)4-benzoquinones (duroquinone). The cellular products of quinone metabolism, hydroquinones and glutathione conjugates, did not cause mitochondrial Ca2+ release. Benzoquinone-induced mitochondrial Ca2+ release was preceded by GSH conjugate formation and NAD(P)H oxidation but followed by mitochondrial swelling. With duroquinone, a slow GSH and NADPH oxidation preceded Ca2+ release, but GSH oxidation did not occur with Se-deficient mitochondria lacking glutathione peroxidase activity. Cyanide-insensitive respiration was also observed with duroquinone but not with benzoquinone, suggesting that duroquinone undergoes redox cycling. GSH was depleted by both arylation and oxidation with 2,6-(CH3O)2-, 2,6-(CH3)2-, 2,5(CH3)2-, and 2,3,5-(CH3)3-benzoquinones. Benzoquinone concentrations that totally depleted GSH did not cause Ca2+ release until intramitochondrial NAD(P)H was oxidized. Ca2+ release was also prevented when NAD(P)H generation was stimulated by the presence of isocitrate or 3-hydroxybutyrate. This suggests that mitochondrial Ca2+ release is associated with NAD(P)H oxidation catalyzed by NADH dehydrogenase with benzoquinone or by the glutathione peroxidase-glutathione reductase system with duroquinone.
...
PMID:Quinone toxicity in hepatocytes: studies on mitochondrial Ca2+ release induced by benzoquinone derivatives. 342 29

Cell lines resistant to ethidium bromide have been developed from cultured mammalian BHK21/C13 cells and these same cells transformed by Rous sarcoma virus (C13/B4). Cells resistant to 2 micrograms ethidium bromide per milliliter have been cloned. One clone of the control and one of the virus-transformed cell lines has been employed for characterization. The resistant cells, in the presence of 2 micrograms ethidium bromide/ml, grow at approximately the same rate as the untreated parental cells. The control cells possess a "normal" karyotype (44 chromosomes), while the corresponding ethidium bromide mutant has a reduced chromosome number of 41 and a number of translocations. The mitochondria displayed morphological alterations compared to the parental lines during the transition phase prior to the isolation of the ethidium bromide-resistant cells. The mitochondria of the ethidium bromide-resistant mutants appear somewhat enlarged with a normal morphology. The effect of ethidium bromide on selected respiratory enzymes in normal and virus-transformed ethidium bromide-resistant baby hamster kidney cells was determined. Ethidium bromide-resistant cells exhibited a depressed level of cytochrome aa3. This depression could not be reversed by growth in ethidium bromide-free media. Ethidium bromide-resistant cells possessed the same cytochrome b, c, and c1 levels per cell as their corresponding parental lines. Purified mitochondria isolated from virus-transformed ethidium bromide-resistant cells exhibited a depression in cytochrome oxidase-specific activity, while the ethidium bromide-resistant control cells did not. All cell lines studied showed a depression in NADH-ferricyanide and NADH-cytochrome c reductase-specific activities relative to their parental BHK21/C13 cells. No increase was observed in virus-transformed ethidium bromide-resistant cells. Ethidium bromide-resistant control cells exhibited a two-fold increase in oligomycin-insensitive adenosine triphosphatase activity relative to their parental cells. All of the cell lines studied possessed equivalent oligomycin-sensitive adenosine triphosphatase-specific activity except for the virus-transformed, dye-resistant mutant, whose activity was increased.
...
PMID:Control and virus-transformed baby hamster kidney cells resistant to ethidium bromide. I. Characterization and the respiratory enzymes. 625 Oct 98

Effects of neutral salts on the drug-metabolizing enzyme system were measured in hepatic microsomes of rats in vitro. Aminopyrine N-demethylation was markedly enhanced by Li2SO4, Na2SO4, and K2SO4. Salts such as LiCi, NaCl, and KCl caused an enhancement of the demethylation following by an inhibition at high concentrations. KBr, Kl, and KSCN always inhibited the demethylation. Aniline hydroxylation, on the contrary, was not stimulated by the sulfates, and all other salts inhibited the hydroxylation with increasing concentration. The effectiveness of the neutral salts on changing aminopyrine or aniline oxidation activity followed Hofmeister's lyotropic series of ions: SCN- greater than 1- Br- greater than Cl- greater than SO4-- as anions and Li+ greater than Na+, K+ as cations. KSCN, Kl and KBr caused both the conversion of cytochrome P-450 to cytochrome P-420 and the inhibition of NADPH cytochrome c reductase activity; however, all other salts used in these experiments showed no change of those components. Enhancement of aminopyrine N-demethylation by the sulfates was reversible. It was concluded that cytochrome P-450 associated with aminopyrine N-demethylation is different from that of aniline hydroxylation in the hydrophobic environment of microsomes, and sulfate or chloride causes an enhancement of only cytochrome P-450 activity associated with the demethylation.
...
PMID:Effects of neutral salts on hepatic microsomal drug-metabolizing enzyme system in rats. 641 37

NADH dehydrogenase from Bacillus subtilis W23 has been isolated from membrane vesicles solubilized with 0.1% Triton X-100 by hydrophobic interaction chromatography on an octyl-Sepharose CL-4B column. A 70-fold purification is achieved. No other components could be detected with sodium dodecyl sulphate polyacrylamide gel electrophoresis. Ferguson plots of the purified protein indicated no anomalous binding of sodium dodecyl sulphate and an accurate molecular weight of 63 000 could be determined. From the amino acid composition a polarity of 43.8% was calculated indicating that the protein is not very hydrophobic. Optical absorption spectra and acid extraction of the enzyme chromophore followed by thin-layer chromatography showed that the enzyme contains 1 molecule FAD/molecule. The enzyme was found to be specific for NADH. NADPH is oxidized at a rate which is less than 6% of the rate of NADH oxidation. The activity of the enzyme as determined by NADH:3-(4'-5'-dimethyl-thiazol-2-yl)2,4-diphenyltetrazolium bromide oxidoreduction is optimal at 37 C and pH 7.5-8.0. The purified enzyme has a Kapp for NADH of 60 microM and a V of 23.5 mumol NADH/min X mg protein. These parameters are not influenced by phospholipids. The enzyme activity is hardly or not at all affected by NADH-related compounds such as ATP, ADP, AMP, adenosine, deoxyadenosine, adenine and nicotinic amide indicating the high binding specificity of the enzyme for NADH.
...
PMID:Purification and characterization of NADH dehydrogenase from Bacillus subtilis. 681 92

Highly purified preparations of the cholate-solubilized respiratory NADH dehydrogenase, isolated from genetically amplified Escherichia coli strains [Jaworowski, A., Campbell, H. D., Poulis, M. I., & Young, I. G. (1981) Biochemistry 20, 2041-2047], have been characterized. Enzyme preparations were shown to contain 70% (w/w) lipid, predominantly phosphatidylethanolamine. One mol of noncovalently bound FAD and approximately 1 mol of ubiquinone/mol of enzyme subunit were detected. The purified enzyme was shown to contain only low levels of Fe and acid-labile S, indicating the absence of iron-sulfur clusters. No Cu, Mo, W, or covalently bound P was detected, and no evidence for other chromophores was obtained from visible and ultraviolet absorption spectra of the purified enzyme or of the delipidated polypeptide prepared by gel filtration in sodium dodecyl sulfate. Protein chemical studies verified that the enzyme consists of a single polypeptide species of Mr 47 000, and the N- and C-terminal cyanogen bromide peptides were identified. The pure enzyme was shown to reconstitute membrane-bound, cyanide-sensitive NADH oxidase activity in membrane vesicles prepared from ndh mutant strains.
...
PMID:Characterization of the respiratory NADH dehydrogenase of Escherichia coli and reconstitution of NADH oxidase in ndh mutant membrane vesicles. 702 Jul 57

A mitochondrial DNA study of seven hydatidiform moles and seven full term placentas as controls was carried out to determine the role played by mitochondrial DNA as the only maternal genome participating in the pathogenesis of these trophoblastic growths. Mitochondrial DNA was digested by restriction enzymes Eco R1 and Hind III, processed by electrophoresis and stained by ethidium bromide. Molar mitochondrial DNA showed two restriction bands at 9416 and 2322 kbs with Eco R1 and one band at 2322 kbs with Hind III, whereas the controls showed three bands of 9416, 4361 and 2322 kbs with Eco 1, and two bands at 4361 and 2322 kbs with Hind III. The results were interpreted as a DNA alteration consistent with a mutation at level of tARN genes, initiating the reading of gen ND2 of Complex I, NADH dehydrogenase and affecting Complex CO III that transcribe cytochrome c and oxidoreductase genes. The alterations are considered as mutations probably resulted from folic acid deficiency at threshold levels during nuclear and mitochondrial DNA synthesis in oogenesis and meiosis that renders anucleated ova (cytoplasts), fertilized, and further accelerated development of a zygote bearing an entire androgenic genome.
...
PMID:[Mitochondrial heredity in hydatidiform moles]. 795 51

Long-term treatment with ethidium bromide of HL-60 cells induced a mitochondria-deficient rho degree cell line, where mitochondrial DNA can not be identified by PCR and cytochrome c oxidase activity was 80% decreased. These cells showed a progressive increase of ascorbate stabilization which was 52% higher in the established rho degree HL-60 cells. Both CoQ10 and NADH-ascorbate free radical reductase of the plasma membrane were increased in rho(0)HL-60 cells compared to parental cells, while NADH-cytochrome c reductase was unchanged. CoQ10 is a component of the ascorbate stabilization activity in the plasma membrane that would provide both a mechanism to deplete the excess of NADH produced in rho(0)HL-60 cells and for resistance to oxidative stress.
...
PMID:Ascorbate stabilization is stimulated in rho(0)HL-60 cells by CoQ10 increase at the plasma membrane. 916 64


1 2 Next >>

---