共查询到17条相似文献,搜索用时 72 毫秒
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硒,谷胱甘肽过氧化物酶和不饱和脂肪酸在鼠亚细胞中的分布 总被引:3,自引:0,他引:3
采和梯度离心和放射性同位素等方法从鼠脑中分离得到髓磷脂、突触囊、轻突触体、重突触体、线粒体6个亚细胞组分,分别测定了各亚细胞中硒-75、谷胱甘肽过氧化物酶和不饱和脂肪酸的含量,结果表明这上结成分在鼠脑亚细胞中的分布呈明显的相关性,同时首次在突触囊、线粒体和微粒体中检测到三咱不同的谷胱甘肽过氧化物酶的活性峰,其中之一可能是红细胞谷胱甘过氧化物酶(EC1.11.1.9)。还就机体的自我保护机制和硒在脑 相似文献
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具有谷胱甘肽过氧化物酶活性的含硒单链抗体酶制备 总被引:1,自引:0,他引:1
利用RT PCR从分泌有谷胱甘肽结合部位的单克隆抗体杂交瘤细胞株 2F3中 ,扩增出单抗重链可变区和轻链可变区基因 .经DNA测序后 ,用Linker(Gly4 Ser1) 3 构建成单链抗体 (scFv)表达载体pTMF scFv ,将重组质粒pTMF scFv转化到大肠杆菌BL2 1(DE3) ,实现了单链抗体的高效表达 .表达的单链抗体占菌体总蛋白 2 5%~ 30 % .该重组蛋白以包涵体形式存在 ,分子量为 30kD .经过金属螯合亲和层析纯化、复性和凝胶过滤纯化 ,得到电泳均一的单链抗体 .再经化学诱变 ,得到含硒单链抗体酶 ,其谷胱甘肽过氧化物酶活性为 330 0U μmol.采用荧光滴定法测定了单链抗体对谷胱甘肽的结合常数 相似文献
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硒、谷胱甘肽过氧化物酶和不饱和脂肪酸在鼠脑亚细胞中的分布 总被引:1,自引:0,他引:1
采用梯度离心和放射性同位素等方法从鼠脑中分离得到髓磷脂、突触囊、轻突触体、重突触体、线粒体6个亚细胞组分。分别测定了各亚细胞中硒-75、谷胱甘肽过氧化物酶和不饱和脂肪酸的含量,结果表明这些成分在鼠脑亚细胞中的分布呈现明显的相关性,同时首次在突触囊、线粒体和微粒体中检测到三种不同的谷胱甘肽过氧化物酶的活性峰,其中之一可能是红细胞谷胱甘肽过氧化物酶(EC1.11.1.9).还就机体的自我保护机制和硒在脑组织中的重要作用进行了讨论。 相似文献
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植物谷胱甘肽过氧化物酶研究进展 总被引:18,自引:1,他引:18
氧化胁迫可诱导植物多种防御酶的产生,其中包括超氧化物歧化酶(SOD,EC1.15.L1)、抗坏血酸过氧化物酶(APX,EC1.11.1.11)、过氧化氢酶(CAT,E.C.1.11.1.6)和谷胱甘肽过氧化物酶(GPXs,EC1.11.1.9).它们在清除活性氧过程中起着不同的作用.GPXs是动物体内清除氧自由基的主要酶类,但它在植物中的功能报道甚少.最近几年研究表明,植物体内也存在类似于哺乳动物的GPXs家族,并对其功能研究已初见端倪.本文综述了有关GPXs的结构以及植物GPXs功能的研究进展. 相似文献
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谷胱甘肽过氧化物酶的硒代半胱氨酸插入元件 总被引:5,自引:0,他引:5
真核生物将硒代半胱氨酸插入蛋白质必需硒代半胱氨酸插入元件(SECIS)的参与,后者位于硒蛋白mRNA的3′非翻译区.采用RNA折叠程序对15个谷胱甘肽过氧化物酶基因进行计算机处理发现,其可能的SECIS中都具有3段保守碱基AUGA-A(G)AA-GA.根据A(G)AA位于顶环或者顶环上游5′臂的突环上,可将SECIS分为Ⅰ型和Ⅱ型结构 相似文献
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化学诱变抗体模拟谷胱甘肽过氧化物酶 总被引:1,自引:1,他引:1
用诱变剂苯甲基磺酰氟活化兔抗人IgM片段上特殊活性部位的丝氨酸残基,经硒化氢处理,则将丝氨酸转变成 硒代半胱氨酸。诱变后的抗体具有谷胱甘肽过氧化物酶活性,其活性为世界最好的GSH-Px模拟物PZ51的70多倍抗体效价为1:8,与没诱变的抗体相似。 相似文献
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化学修饰单克隆抗体模拟谷胱甘肽过氧化物酶 总被引:1,自引:0,他引:1
化学修饰具有底物谷胱甘肽(GSH)结合部位的单克隆抗体(4A4)使其结合部位上的丝氨酸(Ser)转变成谷胱甘肽过氧化物酶(GPX)的催化基因硒代半胱氨酸(SeCys)因而产生高活力的含硒抗体酶(Se-abzyme)突变的4A4(m4A4)的GPX活力达到了天然酶活力的19%并对m4A4的酶学性质和动力学性质进行了研究;硒代谷胱甘肽(GSeH)连到4A4结合部位,其GPX活力由3.86U/μmol提 相似文献
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Ziegler DR Ribeiro LC Hagenn M Siqueira IR Araújo E Torres IL Gottfried C Netto CA Gonçalves CA 《Neurochemical research》2003,28(12):1793-1797
Ketogenic diets have been used in the treatment of refractory childhood epilepsy for almost 80 years; however, we know little about the underlying biochemical basis of their action. In this study, we evaluate oxidative stress in different brain regions from Wistar rats fed a ketogenic diet. Cerebral cortex appears to have not been affected by this diet, and cerebellum presented a decrease in antioxidant capacity measured by a luminol oxidation assay without changes in antioxidant enzyme activities—glutathione peroxidase, catalase, and superoxide dismutase. In the hippocampus, however, we observed an increase in antioxidant activity accompanied by an increase of glutathione peroxidase (about 4 times) and no changes in lipoperoxidation levels. We suggest that the higher activity of this enzyme induced by ketogenic diet in hippocampus might contribute to protect this structure from neurodegenerative sequelae of convulsive disorders. 相似文献
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《Free radical research》2013,47(5-6):343-361
The primary structure of phospholipid hydroperoxide glutathione peroxidase (PHGPx) was partially elucidated by sequencing peptides obtained by cyanogen bromide cleavage and tryptic digestion and by isolating and sequencing corresponding cDNA fragments covering about 75% of the total sequence. Based on these data PHGPx can be rated as a selenoprotein homologous, but poorly related to classical glutathione peroxidase (GPx). Peptide loops constituting the active site in GPx are, however, strongly conserved in PHGPx. This suggests that the mechanism of action involving an oxidation/reduction cycle of a selenocysteine residue is essentially identical in PHGPx and GPx. 相似文献
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R. Schuckelt R. Brigelius-Floh M. Maiorino A. Roveri J. Reumkens W. Strabburger F. Ursini B. Wolf L. Floh 《Free radical research》1991,14(5):343-361
The primary structure of phospholipid hydroperoxide glutathione peroxidase (PHGPx) was partially elucidated by sequencing peptides obtained by cyanogen bromide cleavage and tryptic digestion and by isolating and sequencing corresponding cDNA fragments covering about 75% of the total sequence. Based on these data PHGPx can be rated as a selenoprotein homologous, but poorly related to classical glutathione peroxidase (GPx). Peptide loops constituting the active site in GPx are, however, strongly conserved in PHGPx. This suggests that the mechanism of action involving an oxidation/reduction cycle of a selenocysteine residue is essentially identical in PHGPx and GPx. 相似文献
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Irina Ingold Michaela Aichler Elena Yefremova Antonella Roveri Katalin Buday Sebastian Doll Adrianne Tasdemir Nils Hoffard Wolfgang Wurst Axel Walch Fulvio Ursini José Pedro Friedmann Angeli Marcus Conrad 《The Journal of biological chemistry》2015,290(23):14668-14678
The selenoenzyme Gpx4 is essential for early embryogenesis and cell viability for its unique function to prevent phospholipid oxidation. Recently, the cytosolic form of Gpx4 was identified as an upstream regulator of a novel form of non-apoptotic cell death, called ferroptosis, whereas the mitochondrial isoform of Gpx4 was previously shown to be crucial for male fertility. Here, we generated and analyzed mice with a targeted mutation of the active site selenocysteine of Gpx4 (Gpx4_U46S). Mice homozygous for Gpx4_U46S died at the same embryonic stage (E7.5) as Gpx4−/− embryos as expected. Surprisingly, male mice heterozygous for Gpx4_U46S presented subfertility. Subfertility was manifested in a reduced number of litters from heterozygous breeding and an impairment of spermatozoa to fertilize oocytes in vitro. Morphologically, sperm isolated from heterozygous Gpx4_U46S mice revealed many structural abnormalities particularly in the spermatozoa midpiece due to improper oxidation and polymerization of sperm capsular proteins and malformation of the mitochondrial capsule surrounding and stabilizing sperm mitochondria. These findings are reminiscent of sperm isolated from selenium-deprived rodents or from mice specifically lacking mitochondrial Gpx4. Due to a strongly facilitated incorporation of Ser in the polypeptide chain as compared with selenocysteine at the UGA codon, expression of the catalytically inactive Gpx4_U46S was found to be strongly increased. Because the stability of the mitochondrial capsule of mature spermatozoa depends on the moonlighting function of Gpx4 both as an enzyme oxidizing capsular protein thiols and as a structural protein, tightly controlled expression of functional Gpx4 emerges as a key for full male fertility. 相似文献
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A simple and sensitive method for the simultaneous visualization of glutathione peroxidase and catalase on polyacrylamide gels is described. The procedure included: (I) running samples on a 7. 5% polyacryla-mide gel, (2) soaking the gel in a certain concentration of reduced glutathione (0.25-2.0 mM). (3) soaking the gel in GSH plus HzOz or cumene hydroperoxide, (4) finally staining with a 1% ferric chloride I% potassium ferricyanide solution. The best concentration of glutathione for simultaneous visualization of glutathione peroxidase and catalase was 0.25rnM; I.5mM glutathione was the best concentration for visualization of glutathione peroxidase alone. The method is sensitive enough to detect catalase and glutathione peroxidase in mouse liver homogenates and also it is specific for glutathione peroxidase since other peroxidases such as lactoperoxidase, horseradish peroxidase and glutathione S-transferase cannot be visualized. Using this method, it was found that unlike catalase. glutathione peroxidase is heat resistant (68°C. 1min), but sensitive to 10mM sodium iodoacetate. 相似文献
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《Free radical research》2013,47(2):67-75
A simple and sensitive method for the simultaneous visualization of glutathione peroxidase and catalase on polyacrylamide gels is described. The procedure included: (I) running samples on a 7. 5% polyacryla-mide gel, (2) soaking the gel in a certain concentration of reduced glutathione (0.25–2.0 mM). (3) soaking the gel in GSH plus HzOz or cumene hydroperoxide, (4) finally staining with a 1% ferric chloride I% potassium ferricyanide solution. The best concentration of glutathione for simultaneous visualization of glutathione peroxidase and catalase was 0.25rnM; I.5mM glutathione was the best concentration for visualization of glutathione peroxidase alone. The method is sensitive enough to detect catalase and glutathione peroxidase in mouse liver homogenates and also it is specific for glutathione peroxidase since other peroxidases such as lactoperoxidase, horseradish peroxidase and glutathione S-transferase cannot be visualized. Using this method, it was found that unlike catalase. glutathione peroxidase is heat resistant (68°C. 1min), but sensitive to 10mM sodium iodoacetate. 相似文献