排序方式: 共有70条查询结果,搜索用时 343 毫秒
1.
Action of hypochlorous acid on the antioxidant protective enzymes superoxide dismutase, catalase and glutathione peroxidase. 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The neutrophil enzyme myeloperoxidase generates hypochlorous acid (HOCl) at sites of inflammation. Glutathione peroxidase is very quickly inactivated by low concentration of HOCl. Inactivation of catalase is also rapid, but requires higher HOCl concentrations and the haem appears to be degraded. Inactivation of bovine CuZn superoxide dismutase is slower. Hence superoxide dismutase should not be easily inactivated by HOCl at sites of inflammation, which may contribute to its effectiveness as an anti-inflammatory agent and in minimizing reperfusion injury. 相似文献
2.
Carnosine,homocarnosine and anserine: could they act as antioxidants in vivo? 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Carnosine, homocarnosine and anserine have been proposed to act as antioxidants in vivo. Our studies show that all three compounds are good scavengers of the hydroxyl radical (.OH) but that none of them can react with superoxide radical, hydrogen peroxide or hypochlorous acid at biologically significant rates. None of them can bind iron ions in ways that interfere with 'site-specific' iron-dependent radical damage to the sugar deoxyribose, nor can they restrict the availability of Cu2+ to phenanthroline. Homocarnosine has no effect on iron ion-dependent lipid peroxidation; carnosine and anserine have weak inhibitory effects when used at high concentrations in some (but not all) assay systems. However, the ability of these compounds to interfere with a commonly used version of the thiobarbituric acid (TBA) test may have led to an overestimate of their ability to inhibit lipid peroxidation in some previous studies. By contrast, histidine stimulated iron ion-dependent lipid peroxidation. It is concluded that, because of the high concentrations present in vivo, carnosine and anserine could conceivably act as physiological antioxidants by scavenging .OH, but that they do not have a broad spectrum of antioxidant activity, and their ability to inhibit lipid peroxidation is not well established. It may be that they have a function other than antioxidant protection (e.g. buffering), but that they are safer to accumulate than histidine, which has a marked pro-oxidant action upon iron ion-dependent lipid peroxidation. The inability of homocarnosine to react with HOCl, interfere with the TBA test or affect lipid peroxidation systems in the same way as carnosine is surprising in view of the apparent structural similarity between these two molecules. 相似文献
3.
Formation of hydroxyl radicals in the presence of ferritin and haemosiderin. Is haemosiderin formation a biological protective mechanism? 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M O''Connell B Halliwell C P Moorhouse O I Aruoma H Baum T J Peters 《The Biochemical journal》1986,234(3):727-731
Horse spleen and human spleen ferritins increase the formation of hydroxyl radicals (OH) at both pH 4.5 and pH 7.4 in reaction mixtures containing ascorbic acid and H2O2. The generation of OH is inhibited by the chelator desferrioxamine. Human spleen haemosiderin also accelerates OH generation in identical reaction mixtures, but is far less effective (on a unit iron basis) than ferritin under all reaction conditions. It is proposed that conversion of ferritin into haemosiderin in iron overload is biologically advantageous in that it decreases the ability of iron to promote oxygen-radical reactions. 相似文献
4.
The activities of green cell-free extracts of spinach leavesin performing photochemical transphosphorylation, photosyntheticphosphorylation, the HILL reaction and the light-induced formationof the endogenous reducing substance (ascorbic acid) were followedin parallel during the growth process of the plant. There wasa certain parallelism between the development of the activitiesof photochemical transphosphorylation, of photo-synthetic phosphorylationand of the HILL reaction, activities being low in the earlierstage of growth, reaching a maximum just before efflorescence,and showing thereafter a more or less sharp decline. The activityin the light-induced formation of endogenous reducing substancewas undetectable for the first 35 day-period of growth, reacheda maximum about one week earlier than the other three activities,and again disappeared after 60 days of growth. (Received September 9, 1960; ) 相似文献
5.
Iron ion-dependent modification of bases in DNA by the superoxide radical-generating system hypoxanthine/xanthine oxidase 总被引:15,自引:0,他引:15
Damage to the bases in DNA produced by the hypoxanthine/xanthine oxidase system in the presence of iron ions was studied. The base products in DNA were measured using gas chromatography-mass spectrometry with selected ion monitoring after acidic hydrolysis of DNA and trimethylsilylation. Products identified were cytosine glycol, thymine glycol, 5,6-dihydroxycytosine, 4,6-diamino-5-formamidopyrimidine, 8-hydroxyadenine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, and 8-hydroxyguanine. These are typical hydroxyl radical-induced products of the bases in DNA. 2,6-Diamino-4-hydroxy-5-formamidopyrimidine was the major product, followed by 8-hydroxyguanine, in DNA treated with hypoxanthine/xanthine oxidase/Fe3+-EDTA. The use of Fe3+ did not cause as much damage to the bases in DNA as did the use of Fe3+-EDTA. In both systems, the formation of the products was inhibited by superoxide dismutase, catalase, dimethyl sulfoxide, mannitol, and desferrioxamine, but inhibitions were much stronger in the systems containing EDTA. Hence formation of hydroxyl radicals by a superoxide radical-assisted Fenton reaction is proposed to account for the results obtained. 2,6-Diamino-4-hydroxy-5-formamidopyrimidine, 5,6-dihydroxycytosine, 4,6-diamino-5-formamidopyrimidine, and 8-hydroxyguanine were proposed as the products in DNA to measure if one aims to measure DNA products as indices of oxidative DNA damage involving hydroxyl radicals in vivo. 相似文献
6.
O I Aruoma B Halliwell E Gajewski M Dizdaroglu 《The Journal of biological chemistry》1989,264(34):20509-20512
Incubation of a number of ferric ion chelates with H2O2 at pH 7.4 generated a reactive species able to produce chemical modifications of the bases in DNA that are very similar to those produced in DNA by the hypoxanthine/xanthine oxidase system (Aruoma, O.I., Halliwell, B., and Dizdaroglu, M. (1989) J. Biol. Chem. 264, 13024-13028). Products were identified and quantitated by the use of gas chromatography-mass spectrometry with selected-ion monitoring. Compared with other complexes used, ferric ion-nitrilotriacetic acid produced by far the largest amount of the base products. Typical hydroxyl radical scavengers and superoxide dismutase provided significant decreases in the yields of the products. On this basis, it is proposed that ferric ion complexes react with H2O2 to produce hydroxyl radical; this was also shown using the deoxyribose assay. Inhibition of product formation by superoxide dismutase suggests the involvement of superoxide radical in this reaction. It is likely that hydroxyl radical generated by reaction of the ferric ion-nitrilotriacetic acid complex with H2O2 contributes to the carcinogenicity and nephrotoxicity associated with this chelating agent. 相似文献
7.
Incubation of rat-liver microsomes, previously azide-treated to inhibit catalase, with H2O2 caused a loss of cytochrome P-450 but not of cytochrome b5. This loss of P-450 was not prevented by scavengers of hydroxyl radical, chain-breaking antioxidants or metal ion-chelating agents. Application of the thiobarbituric acid (TBA) assay to the reaction mixture suggested that H2O2 induces lipid peroxidation, but this was found to be due largely or completely to an effect of H2O2 on the TBA assay. By contrast, addition of ascorbic acid and Fe(III) to the microsomes led to lipid peroxidation and P-450 degradation: both processes were inhibited by chelating agents and chain-breaking antioxidants, but not by hydroxyl radical scavengers. H2O2 inhibited ascorbate/Fe (III)-induced microsomal lipid peroxidation, but part of this effect was due to an action of H2O2 in the TBA test itself. H2O2 also decreased the colour measured after carrying out the TBA test upon authentic malondialdehyde, tetraethoxypropane, a DNA-Cu2+/o-phenanthroline system in the presence of a reducing agent, ox-brain phospholipid liposomes in the presence of Fe(III) and ascorbate, or a bleomycin-iron ion/DNA/ascorbate system. Caution must be used in interpreting the results of TBA tests upon systems containing H2O2. 相似文献
8.
Aruoma OI Moncaster JA Walsh DT Gentleman SM Ke B Liang YF Higa T Jen LS 《Free radical research》2003,37(1):91-97
Injection of the glutamate agonist N-methyl-D-aspartate (NMDA) into the vitreous body of rats resulted in severe degeneration of neurons in the retina, with a loss of 81% of ganglion cells and 43% of non-ganglion cells. The cocktail EM-X is a novel antioxidant drink derived from ferment of unpolished rice, papaya and sea-weeds with effective microorganisms (EM-X). In animals treated with an intraperitoneal injection of EM-X, the loss of ganglion cells was reduced to 55% and that of non-ganglion cells to 34% when compared to untreated NMDA-injected retinas. Cell degeneration resulting from NMDA excitotoxicity, is thought to be mediated via oxidative stress mechanisms. The neuroprotective effect of the EM-X in this system is therefore likely to be due, at least in part, to its flavonoids, saponins, vitamin E and ascorbic content. 相似文献
9.
Ahn NS Hu H Park JS Park JS Kim JS An S Kong G Aruoma OI Lee YS Kang KS 《Mutation research》2005,579(1-2):189-199
Although 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has a variety of carcinogenic and noncarcinogenic effects in experimental animals, its role in human carcinogenicity remain controversial. A simian virus 40-immortalized cell line from normal human breast epithelial cells with stem cells and luminal characteristics (M13SV1) was used to study whether TCDD can induce AIG positive colony formation and cause increased cell numbers in a inverted U-shaped dose–response manner. TCDD activated Akt, ERK2, and increased the expression of CYP1A1, PAI-2, IL-lb mRNA, and ERK2 protein levels. TCDD was able to increased phosphorylation and expression of ERK2 in same dose–response manner as AIG positive colony formation. Thus, TCDD induced tumorigenicity in M13SV1, possibly through the phosphorylation of ERK2 and/or Akt. Further, cDNA microarray with 7448 sequence-verified clones was used to profile various gene expression patterns after treatment of TCDD. Three clear patterns could be delineated: genes that were dose-dependently up-regulated, genes expressed in either U-shape and/or inverted U-shape. The fact that these genes are intrinsically related to breast epithelial cell proliferation and survival clearly suggests that they may be involved in the TCDD-induced breast tumorigenesis. 相似文献
10.
Although the cause of dopaminergic cell death in Parkinson's disease (PD) remains unknown, oxidative stress has been strongly implicated. Because of their ability to combat oxidative stress, diet derived phenolic compounds continue to be considered as potential agents for long-term use in PD. This study was aimed at investigating whether the natural phenolic compounds curcumin, naringenin, quercetin, fisetin can be neuroprotective in the 6-OHDA model of PD. Unilateral infusion of 6-OHDA into the medial forebrain bundle produced a significant loss of tyrosine hydroxylase (TH)-positive cells in the substantia nigra (SN) as well as a decreased of dopamine (DA) content in the striata in the vehicle-treated animals. Rats pretreated with curcumin or naringenin showed a clear protection of the number of TH-positive cells in the SN and DA levels in the striata. However, neither pretreatment with quercetin nor fisetin had any effects on TH-positive cells or DA levels. The ability of curcumin and naringenin to exhibit neuroprotection in the 6-OHDA model of PD may be related to their antioxidant capabilities and their capability to penetrate into the brain. 相似文献