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2.
Relationship between melanin content and superoxide dismutase (SOD) activity in the liver of various species of animals 总被引:4,自引:0,他引:4
The scavenger effect of melanin and of superoxide dismutase (SOD) activity on superoxide anion has been shown. In this work we show the relationship between melanin content and SOD activity in livers containing different quantities of melanin which were taken from various species of animals. The mitochondrial SOD activity disappears when the melanin content in the liver is very high; moreover it increases, in the liver of various species of animals examined, proportionally to the decrease of melanin content. No significant variation of the SOD activity localized in the soluble fraction has been detected when related to the melanin content. We think that in the pigmented liver the antioxidant activity of the melanin could mimic part of the function of SOD. The loss of Mn SOD activity could be mediated by a low intracellular level of superoxide anion due to the scavenger effect of melanin on superoxide anion; in fact, it is well known that the biosynthesis of Mn SOD is induced by intracellular levels of superoxide anion. 相似文献
3.
Purification and characterization of thylakoid-bound Mn-superoxide dismutase in spinach chloroplasts 总被引:5,自引:0,他引:5
Thylakoid-bound superoxide dismutase (SOD; EC 1.15.1.1) was solubilized by Triton X-100 from spinach and purified to a homogeneous state. The molecular weight of thylakoid-bound SOD was 52000; the enzyme was composed of two equal subunits. Its activity was not sensitive to cyanide and hydrogen peroxide, and the isolated SOD contained Mn, but neither Fe nor Cu. Thus, the thylakoid-bound SOD is a Mn-containing enzyme. The subunit molecular weight of thylakoid Mn-SOD is the highest among Mn-SODs isolated so far, a fact which might reflect its binding to the membranes. 相似文献
4.
To gain insight into the mechanism of formation of chromosomal aberrations by the tumor promoter phorbolmyristate acetate (PMA) in human lymphocytes, we investigated the effect of antioxidants and inhibitors of arachidonic acid metabolism. Among the antioxidants bovine erythrocyte CuZn superoxide dismutase, glutathione peroxidase, mannitol (a scavenger of hydroxyl radicals), butylated hydroxytoluene and butylated hydroxyanisole were anticlastogenic while catalase and dimethylfuran (a scavenger of singlet oxygen) were inactive. These results show that the induction of aberrations by PMA occurs via indirect action, i.e. the intermediacy of superoxide and hydroxyl radicals. The following inhibitors of arachidonic acid metabolism were strongly anticlastogenic: the cyclo-oxygenase inhibitors indomethacin and flufenamic acid and the lipoxygenase inhibitor BN1015. Imidazole, nordihydroguaiaretic acid BN 1048 and 5,8,11,14-eicosatetraynoic acid were moderately active. The inhibitor of phospholipase A2, fluocinolone acetonide, was also anticlastogenic.
We conclude that the oxidative metabolism of arachidonic acid is involved in the induction of chromosomal aberrations by PMA in human lymphocytes. However, because of the limited selectivity of these drugs, it is not yet possible to identify unambiguously the step(s) in the arachidonic acid cascade responsible for PMA clastogenicity. 相似文献
5.
A chemiluminescent method for measuring the concentration of activated oxygen species (O22 and H2O2) is described. Its main features are: high sensitivity (10?9 M H2O2), its applicability to systems with high optical absorbance in the visible spectral region, a wide linear dynamic range, and the possibility for recording the kinetics of the processes, in which activated oxygen species are involved. 相似文献
6.
Transformed plants with elevated levels of chloroplastic SOD are not more resistant to superoxide toxicity 总被引:29,自引:0,他引:29
The petunia nuclear gene which encodes the chloroplast isozyme of superoxide dismutase, SOD-1, has been fused with an efficient rbcS promoter fragment and 3 flanking region and introduced into tobacco and tomato cells. Transformed plants carrying this chimeric gene have up to 50-fold the levels of SOD-1 which occur in wild-type plants. However, tobacco plants with 30-to 50-fold the normal SOD-1 activity do not exhibit resistance to the light-activated herbicide paraquat. Similarly, tomato plants with 2-to 4-fold increases in SOD-1 do not exhibit tolerance to photoinhibitory conditions known to increase superoxide levels (high light, low temperatures and low CO2 concentrations). Our data indicate that increasing the chloroplastic SOD level in a plant cell is not sufficient to reduce the toxicity of superoxide. 相似文献
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8.
The protective effect of arbutin against potassium bromate-induced oxidative damage in the rat brain
H. Turan Akkoyun Ahmet Uyar Mahire Bayramoglu Akkoyun Aydın Şükrü Bengü Şule Melek Fatma Karagözoğlu Sevinç Aydın Suat Ekin Sinem Aslan Erdem 《Journal of biochemical and molecular toxicology》2023,37(2):e23248
This study aimed to investigate the protective effects of arbutin (ARB) against brain injury induced in rats with potassium bromate (KBrO3). The rats were divided into four groups as Group 1: Control (0.9% NaCl ml/kg/day p.), Group 2: KBrO3 (100 mg/kg (gavage), Group 3: ARB (50 mg/kg/day p.), and Group 4: KBrO3 + ARB (100 mg/kg (gavage) + 50 mg/kg/day p.). At the end of the fifth day of the study, the rats in all groups were killed, and their brain tissues were collected. In the collected brain tissues, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) levels were measured, and routine histopathological examinations were made. The MDA levels in the group that was exposed to KBrO3 were significantly higher than those in the control group (p ˂ 0.001). In comparison to the KBrO3 group, the MDA levels in the KBrO3 + ARB group were significantly lower (p ˂ 0.001). It was observed that SOD and CAT enzyme activity levels were significantly lower in the KBrO3 group compared to the control group (p ˂ 0.001), while these levels were significantly higher in the KBrO3 + ARB group than in the KBrO3 group (p ˂ 0.001). Additionally, the group that was subjected to KBrO3 toxicity, as well as ARB administration, had much lower levels of histopathologic signs than the group that was subjected to KBrO3 toxicity only. Consequently, it was found that KBrO3 exposure led to injury in the brain tissues of the rats, and using ARB was effective in preventing this injury. 相似文献
9.
BackgroundA copper chaperone CCS is a multi-domain protein that supplies a copper ion to Cu/Zn-superoxide dismutase (SOD1). Among the domains of CCS, the N-terminal domain (CCSdI) belongs to a heavy metal-associated (HMA) domain, in which a Cys-x-x-Cys (CxxC) motif binds a heavy metal ion. It has hence been expected that the HMA domain in CCS has a role in the metal trafficking; however, the CxxC motif in the domain is dispensable for supplying a copper ion to SOD1, leaving an open question on roles of CCSdI in CCS.MethodsTo evaluate protein-protein interactions of CCS through CCSdI, yeast two-hybrid assay, a pull-down assay using recombinant proteins, and the analysis with fluorescence resonance energy transfer were performed.ResultsWe found that CCS specifically interacted with another copper chaperone HAH1, a HMA domain protein, through CCSdI. The interaction between CCSdI and HAH1 was not involved in the copper supply from CCS to SOD1 but was mediated by a zinc ion ligated with Cys residues of the CxxC motifs in CCSdI and HAH1.ConclusionWhile physiological significance of the interaction between copper chaperones awaits further investigation, we propose that CCSdI would have a role in the metal-mediated interaction with other proteins including heterologous copper chaperones. 相似文献
10.
蜂花粉抗脑衰老的实验动物研究 总被引:1,自引:0,他引:1
蜂花粉抗脑衰老的实验动物研究蒋滢,杨炳华,黄美英苏州医学院生化教研室苏州2150072探索衰老机制,寻求延缓衰老的有效途径是生命科学中的重大问题,也是亟待解决的实际问题。脑是指挥全身一切活动的中枢,脑组织特别容易遭受自由基及活性氧的损伤,因此防治脑衰... 相似文献