Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

F344 Male rats weighting between 90 and 110 gm were given 90 ppm diethylnitrosamine in their drinking water for 5 weeks. Seven weeks after the administration of carcinogen was completed, the rats were sacrificed and sections of their livers were embedded in methacrylate. Serial sections 2 or 4 micron in thickness demonstrated the presence of gamma-glutamyl transpeptidase, acid phosphatase, adenosine triphosphatase, aldehyde dehydrogenase, alkaline phosphatase, alpha-naphthyl butyrate esterase, DT diaphorase, glucose-6-phosphate dehydrogenase, and 5'-nucleotidase activity and glycogen. The use of 4-micron sections of methacrylate-embedded tissue allows the evaluation of many more phenotypic markers in serial sections than is currently possible with frozen sections.
 ...
PMID:Examination of enzyme-altered foci with gamma-glutamyl transpeptidase, aldehyde dehydrogenase, glucose-6-phosphate dehydrogenase, and other markers in methacrylate-embedded liver. 287 68

Young adult rats absorbed 50 p.p.m. Cd2+ added to drinking water. After 6 weeks, 3, 6 and 9 months of treatment, the ultrastructural condition of liver, kidney and muscle was observed by electron microscopy. The choice of these tissues was determined by their differences in the capacity to accumulate Cd2+: the liver is able to concentrate a considerable amount of metal, but redistributes it throughout the entire organism, while the kidney collects it in view of its elimination. Muscle contains the least Cd2+. A general regression in mitochondria cristae accompanied by a vesiculation and a fragmentation of endoplasmic reticulum appeared simultaneously in the three tissues, at as early as 6 weeks of treatment, and extended progressively with its continuation supporting evidence of a general attack of the intracellular membrane systems. Cd2+ stimulation of membrane-degrading enzymes such as phospholipases and proteases was suggested. A concomitant diminution in glycogen stores was noted. Active synthesis of neutral lipids, especially cholesterol esters, took place in liver mitochondria of treated rats in collaboration with rough endoplasmic reticulum, and progressively generated a multiplication of electron-transparent inclusions in cytoplasm. Isolated mitochondria from liver, kidney and muscle of Cd2+-treated rats maintained partial energy coupling, but displayed a rapid early fall in cytochrome oxidase followed by a partial restoration after 6 months of treatment, and a progressively slackening of succinate dehydrogenase. Isolated vesicles of liver mitochondria inner membrane of treated rats behaved as intact mitochondria, indicating changes inside the membrane itself. Addition in vitro of the metal ion to mitochondria and also to inner membrane vesicles isolated from control rats revealed that Cd2+ was able to stop completely succinate dehydrogenase, but was totally ineffective on cytochrome oxidase. Membrane fixation of Cd2+ on the flavoprotein or SH associated with succinate dehydrogenase is proposed. Considering the close parallelism of the extensive depression of microsomal NADPH cytochrome c reductase and the rapid fall in mitochondrial cytochrome oxidase, it is suggested that an indirect inhibition process occurs, through Cd2+-induced diminution of a constituent common to all cytochromes in the cell.
 ...
PMID:Mitochondria alterations in Cd2+-treated rats: general regression of inner membrane cristae and electron transport impairment. 293 99

The interaction between horse heart cytochrome c and Chromatium vinosum flavocytochrome c-552 was studied using the water-soluble reagent 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). Treatment of flavocytochrome c-552 with EDC was found to inhibit the sulfide: cytochrome c reductase activity of the enzyme. SDS gel electrophoresis studies revealed that EDC treatment led to modification of carboxyl groups in both the Mr 21 000 heme peptide and the Mr 46 000 flavin peptide, and also to the formation of a cross-linked heme peptide dimer with an Mr value of 42 000. Both the inhibition of sulfide: cytochrome c reductase activity and the formation of the heme peptide dimer were decreased when the EDC modification was carried out in the presence of cytochrome c. In addition, two new cross-linked species with Mr values of 34 000 and 59 000 were formed. These were identified as cross-linked cytochrome c-heme peptide and cytochrome c-flavin peptide species, respectively. Neither of these species were formed in the presence of a cytochrome c derivative in which all of the lysine amino groups had been dimethylated, demonstrating that EDC had cross-linked lysine amino groups on native cytochrome c to carboxyl groups on the heme and flavin peptides. A complex between cytochrome c and flavocytochrome c-552 was required for cross-linking to occur, since ionic strengths above 100 mM inhibited cross-linking.
 ...
PMID:The use of a water-soluble carbodiimide to study the interaction between Chromatium vinosum flavocytochrome c-552 and cytochrome c. 300 55

To elucidate the mechanism by which TRH and its metabolite, histidyl-proline diketopiperazine (cyclo(His-Pro], act on the maturation of homoiothermy, the chronic effects of intrathecal administration of the peptides on body temperature, serum thyroid hormone levels, and mitochondrial energy-producing enzyme activities were examined in neonatal rats. The two peptides or an equimolar mixture of both were injected intrathecally at a dose of 3, 6 and 9 nmol for 7 consecutive days during the 1st, 2nd or 3rd week of life, respectively. Control rats were treated with saline and they were sacrificed at 6 weeks of age. Although food and water intake were not decreased, body weight gain was slightly reduced in the rats treated with TRH or cyclo(His-Pro) during the 1st and 2nd week of life, whereas the mixture-treated rats showed normal weight gain. Body temperature at 25 degrees C was not different in the TRH- and cyclo(His-Pro)-treated groups, whereas after cold exposure (5 degrees C for 3 h), the groups treated with TRH during the 1st and 2nd week of life had an impaired thermoregulation at 5 weeks of age. Serum T4 and T3 concentrations were similar in all groups, except in the rats treated with TRH during the 2nd week of life; their thyroid hormone levels were slightly reduced. The TRH treatment suppressed mitochondrial cytochrome c reductase and glucose-6-phosphatase activities, whereas cyclo(His-Pro) reduced cytochrome c reductase and malic enzyme activities. In contrast, alpha-glycerophosphate dehydrogenase was enhanced by both treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Long-term effects of thyrotropin-releasing hormone and histidyl-proline diketopiperazine on the maturation of homeothermia and mitochondrial enzyme activities in neonatal rats. 314 9

To better understand the etiology of cancer in fish from polluted waters, the impact of environmental contaminants on xenobiotic metabolism of channel catfish (Ictalurus punctatus) from a highly polluted water body, Devil's Swamp in southeastern Louisiana, has been investigated. Fish from Devil's Swamp bioaccumulated polynuclear aromatic hydrocarbons (PAH), chlorinated hydrocarbon insecticides (CHI), and polychlorinated biphenyls (PCB) in fat tissue, the latter exceeding 7000 ppb. Reference catfish from the University farm, Ben Hur, were virtually devoid of PAH, CHI, and PCB. Liver microsomal enzymes (MFO) from Devil's Swamp fish were markedly induced. The specific content of cytochromes P450 and b5 and the specific activities of NAD(P)H-cytochrome c reductase were two to three times higher than those of Ben Hur fish. Consistent with this induction, a 9000g supernatant from Devil's Swamp but not Ben Hur fish activated 2-aminofluorene and benzo[a]pyrene (BP) to mutagens in the Ames test. BP metabolism by Devil's Swamp fish liver microsomes was inhibited to a greater extent by alpha-naphthoflavone than was BP metabolism by Ben Hur fish microsomes. This finding indicates that the induced activity in the Devil's Swamp fish liver was the result of P450 isozymes characteristic of PAH/PCB induction. Thus, exposure of fish to environmental pollutants can alter MFO leading to enhanced metabolic activation of promutagens to mutagens.
 ...
PMID:Hepatic monooxygenase induction and promutagen activation in channel catfish from a contaminated river basin. 314 89

This semi-automated colorimetric assay for the MB isoenzyme of creatine kinase (EC 2.7.3.2) is based on a monoclonal antibody ("Conan-MB") specific for this isoenzyme and is a modification of a previously published method (Vaidya et al., Clin Chem 1986;32:657-63). A 0.64-cm bead coated with 2 to 3 micrograms of antibody is incubated with 100 microL of serum and 10 microL of 0.2 mol/L beta-mercaptoethanol for 1 h at room temperature, to extract CK-MB. The beads are washed with de-ionized water and incubated with CK substrate for 45 min at 37 degrees C. A solution containing trans-1,2-diaminocyclohexane-N,N,N', N'-tetraacetic acid, p-iodonitrotetrazolium violet, and diaphorase is added and the resulting colored product is measured at 492 nm. The standard curve is linear to 200 U of CK-MB per liter, and analytical recovery is 97-113%. Total assay CV for low (9.7 U/L) and high (50.7 U/L) quality-control materials was 14.1% (n = 1878) and 11.6% (n = 1842), respectively. CK-MB activity correlated well (r = 0.978, n = 226) with CK-MB measured by a two-site mass immunoassay, and 99.4% of samples with CK-MB greater than or equal to 12 U/L (n = 347) were verified by electrophoresis on agarose.
 ...
PMID:Semi-automated direct colorimetric measurement of creatine kinase isoenzyme MB activity after extraction from serum by use of a CK-MB-specific monoclonal antibody. 334 10

Mitochondrial NADH dehydrogenase has been purified from rat liver mitochondria by protamine sulfate fractionation and DEAE-Sephadex chromatography. The enzyme is water-soluble and its molecular weight has been estimated at 400 +/- 50 kilodaltons. NADH-ferricyanide reductase and NADH cytochrome c reductase activities have been studied and the kinetic parameters have been determined. Both substrates, NADH and the electron acceptor (ferricyanide or cytochrome c) have an inhibitor effect on the reductase activities and the kinetic mechanism of the enzyme is ping-pong bi-bi.
 ...
PMID:Isolation and characterization of a NADH-dehydrogenase from rat liver mitochondria. 361 8

Investigations were carried out into the activity and localization of NADH-dependant diaphorase in boar spermatozoa. Semen samples were collected from healthy boars, used in A.I. centers. The enzyme was extracted with distilled water and Triton X-100. Two forms of diaphorase were found-water-soluble and Triton X-100 soluble, showing low activity-0.36 U/ml and 0.26 U/ml. The enzyme was localized in the mitochondria, manifesting different intensities of reaction between sperm cells in the same ejaculate. It was found, that a part of the mitochondria and outer doublets showed positive reaction. It is suggested that the enzyme regulates the ratio between reduced and oxidized forms of NADH, takes part in the energy balance and possibly in the mechanism of sperm motility.
 ...
PMID:Activity and localization of NADH-dependant oxidoreductase (diaphorase) in boar spermatozoa. 366 51

The quenching of fluorescence of n-(9-anthroyloxy)stearic acids and other probes by different ubiquinone homologues and analogues has been exploited to assess the localization and lateral mobility of the quinones in lipid bilayers of model and mitochondrial membranes. The true bimolecular collisional quenching constants in the lipids together with the lipid/water partition coefficients were obtained from Stern-Volmer plots at different membrane concentrations. A monomeric localization of the quinone in the phospholipid bilayer is suggested for the short side-chain ubiquinone homologues and for the longer derivatives when cosonicated with the phospholipids. The diffusion coefficients of the ubiquinones, calculated from the quenching constants either in three dimensions or in two dimensions, are in the range of (1-6) X 10(-6) cm2 s-1, both in phospholipid vesicles and in mitochondrial membranes. A careful analysis of different possible locations of ubiquinones in the phospholipid bilayer, accounting for the calculated diffusion coefficients and the viscosities derived therefrom, strongly suggests that the ubiquinone 10 molecule is located within the lipid bilayer with the quinone ring preferentially adjacent to the polar head groups of the phospholipids and the hydrophobic tail largely accommodated in the bilayer midplane. The steady-state rates of either ubiquinol 1-cytochrome c reductase or NADH:ubiquinone 1 reductase are proportional to the concentration of the quinol or quinone substrate in the membrane. The second-order rate constants appear to be at least 3 orders of magnitude lower than the second-order constants for quenching of the fluorescent probes; this is taken as a clear indication that ubiquinone diffusion is not the rate-determining step in the quinone-enzyme interaction.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Determination of partition and lateral diffusion coefficients of ubiquinones by fluorescence quenching of n-(9-anthroyloxy)stearic acids in phospholipid vesicles and mitochondrial membranes. 373 Mar 66

A cloned fetal Syrian hamster lung epithelial cell line (M3E3/C3) was used to compare the influence of two different culture conditions on the degree of cellular differentiation and susceptibility of the cells to undergo malignant transformation by a precarcinogen, benzo(a)pyrene. Conventional conditions consisted of growth medium containing Roswell Park Memorial Institute Medium 1640, pyruvate, and fetal bovine serum and a substratum of plastic. Complex conditions comprised the growth medium supplemented with insulin, hydrocortisone, estradiol, epidermal growth factor, transferrin, and cholera toxin and a substratum of collagen gel. Under the complex culture conditions, there was extensive development of endoplasmic reticulum and Golgi vesicles, whereas under conventional conditions these organelles were only minimally developed. This was correlated with 1.5-1.8 times enhancement of ethoxycoumarin deethylase and reduced nicotinamide adenine dinucleotide phosphate-dependent cytochrome c reductase activities. Decomposition of added benz(a)anthracene into water-soluble compounds increased with the period of incubation and reached about 40% of initial benz(a)anthracene (50 micrograms/10 ml/flask) at 48 h under the complex conditions, whereas under the conventional conditions only less than 4% decomposition occurred. Benzo(a)pyrene in the dose range 2-8 micrograms/ml was strongly cytotoxic and caused significant anchorage independent transformation only under complex culture conditions. Transformed cells produced tumors in two of four hamsters during 8 months following s.c. injection within 48 h of birth. These results suggest that the complex culture conditions predisposed the cloned fetal epithelial cells to malignant transformation by benzo(a)pyrene through stimulation of cellular differentiation and development of enzyme systems capable of activating it metabolically.
 ...
PMID:Predisposition of cloned fetal hamster lung epithelial cells to transformation by a precarcinogen, benzo(a)pyrene, using growth hormone supplementation and collagen gel substratum. 380 97


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>