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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effect of novel aromatic GABA derivative (AFA) on lipid peroxidation (LP) was studied in the male rats of the Wistar strain. The morphine-received animals had the higher level of LP in blood plasma, decreased level of total antioxidant activity, the increased rate of LP in the ascorbate-induced system in liver homogenate. In the case of AFA administration with morphine, all the above mentioned effects were almost withdrawn.
Biochem Mol Biol Int 1995 May
PMID:Effect of novel aromatic derivative of GABA on lipid peroxidation in chronically morphinized rats. 766 7

The generation of free radicals by Cr(IV) from lipid hydroperoxides was investigated by ESR spin trapping. The spin trap used was 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Reaction of Cr(VI) with ascorbate was used as a source of Cr(IV). Incubation of Cr(VI) with ascorbate generated Cr(IV) and Cr(V). Addition of cumene hydroperoxide generated DMPO/R adduct with an enhancement of Cr(V) signal. Addition of Mn(II), whose function is to remove Cr(IV), caused dose-dependent inhibition of DMPO/R formation. Similar results were obtained using t-butyl hydroperoxide. Metal ion chelators, deferoxamine, 1,10-phenanthroline and diethylenetriaminepentaacetic acid inhibited DMPO/R formation in the order of deferoxamine > 1,10-phenanthroline > diethylenetriaminepentaacetic acid. The results suggest the possible role of Cr(IV) and its mediated free radical generation from lipid hydroperoxides in the mechanism of Cr(VI) carcinogenesis.
Biochem Mol Biol Int 1995 Jun
PMID:Generation of free radicals by Cr(IV) from lipid hydroperoxides and its inhibition by chelators. 766 36

Salicylate is widely used as a stable trap for the highly reactive hydroxyl radical. The purpose of this study was to determine whether the addition of salicylate to hearts subjected to ischemia and reperfusion was able to prevent some injury. Salicylate was able to inhibit mitochondrial damage, and preserved ascorbate and alpha-tocopherol depletion due to ischemia/reperfusion in rat hearts. It did not prevent the elevation of low molecular weight iron. We conclude that salicylate functions as an antioxidant and afforded protection against ischemia and reperfusion.
Res Commun Mol Pathol Pharmacol 1994 Dec
PMID:Salicylate in the perfusate during ischemia/reperfusion prevented mitochondrial injury. 771 5

The involvement of reactive oxygen species in chromate-induced genotoxicity has been postulated. Because intracellular antioxidants help in eliminating the reactive species of oxygen, we have investigated both the prooxidant and antioxidant status of human leukemic T-lymphocyte MOLT4 cells exposed to nontoxic levels of chromium(VI) in culture. The cells treated with 0-->200 microM potassium chromate in a salts/glucose medium for 2 h were found to contain significantly lower levels of both small molecular weight and macromolecular antioxidants. In particular, the levels of glutathione and ascorbate were found to decrease with increased doses of chromate exposure in a dose-dependent manner. As little as 10 microM chromate was found to decrease these small molecular weight antioxidants significantly (p < 0.01). The macromolecular antioxidants, such as glutathione peroxidase, catalase, glutathione reductase, glucose-6-phosphate dehydrogenase and superoxide dismutase were also significantly (p < 0.01) decreased by exposing the cells to as little as 10 microM chromate. Concomitantly, there was a dose-dependent increase in intracellular H2O2 accumulation in cells exposed to chromium(VI). These results indicate that chromate-induced genotoxicity may be due, at least in part, to decreased levels of intracellular antioxidants in conjunction with an increased production of the reactive oxygen species.
Mol Cell Biochem 1995 Jan 12
PMID:Alterations in the prooxidant and antioxidant status of human leukemic T-lymphocyte MOLT4 cells treated with potassium chromate. 775 43

Ozone (5 mumol.min-1) inhibited the human erythrocyte membrane Na(+)-K+ ATPase (EC.3.6.1.39) activity in a time dependent manner. Inhibition was more pronounced for the first 5 min of ozone exposure in the directly ozone exposed membranes than in the membranes prepared from ozone exposed erythrocytes. However, Na(+)-K+ ATPase activities of both preparations were inhibited to the same extent (about 70%) at the end of 10 min ozone exposure. It was also determined that there was a close relationship between the decrease of enzyme activity and the increase in the thiobarbituric acid reactive substances in both types of preparations. Na(+)-K+ ATPase was inhibited by ozone even at the presence of vitamin E or vitamin C. However, the degree of the inhibitions and the amounts of thiobarbituric acid reactive products formed were smaller than the corresponding values found in the absence of these vitamins.
Biochem Mol Biol Int 1994 Aug
PMID:Effects of ozone on the activity of erythrocyte membrane Na(+)-K+ ATPase. 780 27

The yeast Saccharomyces cerevisiae contains a plasma membrane reductase activity associated with the gene product of the FRE1 locus. This reductase is required for Fe(III) uptake by this yeast; transcription from FRE1 is repressed by iron (Dancis, A., Klausner, R. D., Hinnebusch, A. G., and Barriocanal, J. G. (1990) Mol. Cell. Biol. 10, 2294-2301). We show here that Cu(II) is equally efficient at repressing FRE1 transcription and is an excellent substrate for the Fre1p reductase. This reductase activity is required for 50-70% of the uptake of 64Cu by wild type cells. Under conditions of low Fre1-dependent activity, cells retain 30-70% of Cu(II) reductase activity but only 8-25% of Fe(III) reductase activity. While Fre1p-dependent activity is 100% inhibitable by Pt(II), this residual Cu(II) reduction is insensitive to this inhibitor. The data suggest the presence of a Fre1p-independent reductase activity in the yeast plasma membrane which is relatively specific for Cu(II) and which supports copper uptake in the absence of FRE1 expression. The gene product of MAC1, which is required for regulation of FRE1 transcription, is also required for expression of Cu(II) reduction activity. This is due in part to its role in the regulation of FRE1; however, it is required for expression of the putative Cu(II) reductase, as well. Similarly, a gain-of-function mutation, MAC1up1, which causes elevated and unregulated transcription from FRE1 and elevated Fe(III) reduction and 59Fe uptake exhibits a similar phenotype with respect to Cu(II) reduction and 64Cu uptake. Ascorbate, which reduces periplasmic Cu(II) to Cu(I), suppresses the dependence of 64Cu uptake on plasma membrane reductase activity as is the case for ascorbate-supported 59Fe uptake. The close parallels between Cu(II) and Fe(III) reduction, and 64Cu and 59Fe uptake, strongly suggest that Cu(II) uptake by yeast involves a Cu(I) intermediate. This results in the reductive mobilization of the copper from periplasmic chelating agents, making the free ion available for translocation across the plasma membrane.
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PMID:Evidence for Cu(II) reduction as a component of copper uptake by Saccharomyces cerevisiae. 781 63

Iron ions play a central role in .OH radicals formation and induction of oxidative stress in living organisms. Iron-catalyzed .OH radical formation degrades deoxyribose to thiobarbituric acid reactive substances (TBA-RS). This paper analyzes kinetic properties of the Fe(III)-EDTA-catalyzed deoxyribose degradation in the presence of ascorbate. The yield of TBA-RS formation in the presence of EDTA was 4-fold higher than in its absence, contrasting with results reported elsewhere, Cu(II)-EDTA and Fe(III)-citrate were unable to catalyze deoxyribose degradation. The dependence on deoxyribose concentration was fitted to a Lineweaver Burk-like plot and it was calculated that approximately 4.5 mM deoxyribose scavenged half of the .OH radicals formed. The data for Fe(III)-EDTA concentration dependence could also be fitted to a rectangular hyperbolic function. This function was linear up to 1 microM added FeCl3 and this property could be utilized as an assay for the estimation of submicromolar iron concentrations. Submicromolar concentrations of iron could induce measurable yields of TBA-RS. Differences of as little as 0.1 microM Fe(III)-EDTA could be reproducibly detected under optimum experimental conditions, above a consistent background absorbance that was equivalent to 0.35 +/- 0.05 microM Fe(III)-EDTA and represented contaminating iron in the reactants that could not be removed with Chelex-100. The low method determination limit makes the deoxyribose degradation reaction potentially useful as a new, highly sensitive and cost effective assay for iron quantification.
Mol Cell Biochem 1994 Aug 17
PMID:Deoxyribose degradation catalyzed by Fe(III)-EDTA: kinetic aspects and potential usefulness for submicromolar iron measurements. 784 80

Effects of oxidative stress on isolated rat ventricular myocytes were studied. Myocyte viability was determined by the ability of these cells to retain rod-shaped morphology and to exclude trypan blue. The mean life time of myocytes was quantitated using the Weibull distribution function. Superfusion with 200 microM tert-butyl hydroperoxide (t-BHP) led to a time-dependent loss of cell viability, generation of the products of lipid peroxidation, oxidation of protein and non-protein thiols, a decrease in [ATP]i and in the cellular energy charge. Dithiothreitol (DTT, 5 mM) prolonged survival of myocytes exposed to t-BHP, attenuated oxidation of protein and non-protein thiols, and preserved the energy charge. Exposure to DTT did not affect the concentration of t-BHP-generated lipid peroxidation products. Promethazine (1 microM) prevented t-BHP-induced increase in the concentration of lipid peroxidation products, but did not prevent either loss of thiols or loss of cell viability. Superfusion with N-ethylmaleimide (NEM, 5 microM) also led to loss of cell viability, with accompanying decreases in protein and non-protein thiols, ATP and energy charge without the accumulation of the products of lipid peroxidation. Superfusion with FeSO4 (400 microM) and ascorbate (1 mM), (Fe-Asc) did not result in loss of cell viability or a decrease protein thiols or the energy charge. Superfusion with Fe-Asc, did, however, lead to a slight decrease in the concentration of non-protein thiols and ATP and a large increase in the concentration of lipid peroxidation products. Accumulation of lipid peroxidation products induced by Fe-Asc was prevented by promethazine.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biochem 1994 Aug 17
PMID:Biochemical mechanism of irreversible cell injury caused by free radical-initiated reactions. 784 83

In the studies described here rat liver microsomes containing labeled palmitic, stearic, oleic or linoleic acids were incubated with fatty acid binding protein (FABP) and the rate of removal of 14C-labeled fatty acids from the membrane by the soluble protein was measured using a model system. More unsaturated than saturated fatty acids were removed from native liver mircrosomes incubated with similar amounts of FABP. The in vitro peroxidation of microsomal membranes mediated by ascorbate-Fe++, modified its fatty acid composition with a considerable decrease of the peroxidizability index. These changes in the microsomes facilitated the removal of oleic and linoeic acids by FABP, but the removal of palmitic and stearic acids was not modified. This effect is proposed to result from a perturbation of membrane structure following peroxidation with release of free fatty acids from susceptible domains.
Mol Cell Biochem 1994 Aug 31
PMID:Interaction of rat liver microsomes containing saturated or unsaturated fatty acids with fatty acid binding protein: peroxidation effect. 784 87

In order to gain a degree of insight into the mitochondrial component/s responsible of the mitochondria-red light interaction, isolated rat liver mitochondria were irradiated with a Helium-Neon laser (energy dose 2 Joules/cm2, light power 10 mW) and measurements made of the activity of cytochrome c oxidase. A low, but statistically significant increase in the oxygen uptake was found, as polarographically measured, in the presence of rotenone and antimycin A, with ascorbate and TMPD used as substrate pair. Measurements were also made both of the electron transfer and of proton pumping activity: as a result of a major stimulation in the proton pumping activity, about 55% increase of <--H+/e- ratio was found in irradiated mitochondria.
Biochem Mol Biol Int 1994 Oct
PMID:Increase in <--H+/e- ratio of the cytochrome c oxidase reaction in mitochondria irradiated with helium-neon laser. 786 9


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