超氧化物歧化酶(SOD)

一、产品概述 SOD在耗氧的生物中存在,催化下列反应:2H~+2O_2~-→H_2O_2+O_2。从低等生物的微生物到高等动植物都含有SOD,在体内起防御活性氧障碍的作用。 哺乳动物细胞质中的SOD是草绿色的酶,是分子量为3.1-3.2万的亚基的二聚体,各亚基各含1原子的铜和锌。血液中的血铜蛋白、肝脏中的肝铜蛋白均为此酶。     

桔小实蝇超氧化物歧化酶基因SOD3的克隆及表达分析

采用反转录聚合酶链式反应(RT-PCR)和快速扩增c DNA末端(RACE)技术克隆桔小实蝇SOD3基因,并命名为Bdor SOD3。Bdor SOD3阅读框全长531 bp,编码176个氨基酸,第1-20位氨基酸为其信号肽区域;该蛋白序列与桔小实蝇的另外一种SOD蛋白AGE89778.1序列的一致性最高,达98.7%;采用Swiss-model在线软件模拟构建Bdor SOD3蛋白的三维结构;采用半定量PCR方法,研究Bdor SOD3基因大肠杆菌诱导后的表达情况,结果表明,Bdor SOD3在处理与对照的24 h、48 h都有表达,但Bdor SOD3在处理后48 h表达量明显升高,结果暗示Bdor SOD3与桔小实蝇蛹对大肠杆菌的免疫机制有关。     

人铜锌超氧化物歧化酶cDNA的克隆,测序及表达

用逆转录聚合酶链反应（ＲＴＰＣＲ）,以人胎肝组织总ＲＮＡ为模板,扩增了人铜锌超氧化物歧化酶（ｈＣｕ,ＺｎＳＯＤ）的ｃＤＮＡ,并进行序列分析,将该ｈＣｕ,ＺｎＳＯＤｃＤＮＡ重组到Ｔ７启动子控制下的分泌型表达载体ｐＥＴ２２ｂ（＋）中,构建表达质粒ｐＥＴＳＯＤ,并转化大肠杆菌ＢＬ２１（ＤＥ３）。ＳＤＳＰＡＧＥ及蛋白质印迹分析表明,经１ｍｍｏｌ／Ｌ异丙基硫代βＤ半乳糖苷（ＩＰＴＧ）诱导后,可高效表达一分子量为１９ｋＤ的蛋白质,与抗人ＳＯＤ多抗有特异的免疫反应,表达量约为菌体总蛋白质的３０％,具有特异性ＳＯＤ酶活性,酶活力可达１７９７ｕ／ｍｌ培基。     

修饰SOD及未修饰SOD的稳定性比较研究

测定了分子修饰ＳＯＤ的酶活力及其在不同温度下的稳定性,与未修饰的ＳＯＤ进行了比较,对在不同温度下测定的结果进行数据处理,经推算得出分子修饰ＳＯＤ在２５℃条件下,保存９５％的酶活力达３．５年,保存９０％的酶活力达７．２年,未修饰ＳＯＤ在２５℃条件下,保存９５％的酶活力为１０３ｄ,保存９０％的酶活力为２１３ｄ。     

虫生真菌分子生物学研究进展*

虫生真菌分子生物学的在研究自开展以来,有20多种与杀虫毒力相关的蛋白酶得到纯化,而与之相对应的基因也分别得到克隆、测序。陆续的基因克隆表明,虫生具菌中的重要毒力基因以基因族的形式存在,在精确的表达调控下以适应不同的寄主种类和不同的环境条件。基因工程研究表明,以增加毒力基因拷贝的方式可显提高虫生真菌的杀虫速率,带有外源基因标记的菌株也是环境释放示综研究的良好材料及方法。     

植物超氧化物歧化酶（SOD）的研究进展

超氧化物歧化酶(superoxide dismutase,SOD)在需氧原核生物和真核生物中广泛存在,是活性氧清除系统中第一个发挥作用的抗氧化酶。植物正常代谢过程和在各种环境胁迫下均能产生活性氧和自由基,活性氧和自由基的积累引起细胞结构和功能的破坏。SOD岐化超氧物阴离子自由基生成过氧化氢和分子氧,在保护细胞免受氧化损伤过程中具有十分重要的作用。本文综述了SOD的功能、在细胞中的分布、表达调控和与植物抗逆性的关系。 Abstract:Superoxide Dismutases (SODs) are ubiquitously expressed antioxidant enzyme in aerobic organisms and catalyze dismutation of superoxide anion to hydrogen and molecular oxygen,the first step in active oxygen-scavenging systems.SODs play a central role in protecting cells against the toxic effects of reactive oxygen species generated during normal cellular metabolic activity or as a result of various environmental stresses.This paper reviews the expression and regulation of Sod genes and their functional role(s) during development and in response to stresses.     

超氧化物歧化酶(SOD)研究进展

环境胁迫使植物细胞中积累大量的活性氧,从而导致蛋白质、膜脂、DNA及其它细胞组分的严重损伤。植物体内有效清除活性氧的酶类包括超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)等,其中研究最深入的是SOD。利用基因工程策略增加这些物质在植物体内的含量,从而获得抗逆转基因植株。     

番茄蔗糖代谢关键基因的分子生物学研究

蔗糖代谢相关的酶类主要有转化酶、蔗糖合成酶和蔗糖磷酸合成酶。该文着重对番茄中这些酶的编码基因表达与转基因方面的近期研究进行分析评述。     

重要观赏兰科植物的分子生物学研究进展

兰科植物是开花植物中最大的家族之一,分子标记技术应用于兰科植物的分类鉴定和品种鉴别,为兰花的分类提供了分子水平的证据,也为兰花保护策略和措施的制定提供了理论基础.兰科植物表现有高度特异的形态、结构和生理特性,是研究花着色机理和子房发育的理想对象.兰花离体培养开花系统的建立,可以用来探明兰花从营养生长向生殖生长的转变机制,是研究花的分化和发育的理想材料.兰花具有特异的查尔酮合成酶(CHS)基因和二氢叶酸还原酶(DFR)基因等控制花色素的合成,DOHI基因控制石斛兰花芽的形成和提早开花,PHAL039基因和ACC合成酶基因在蝴蝶兰授粉后的子房发育中起着重要的调控作用,这些特异基因的分离和克隆为兰花花的分化、发育及着色机制提供了分子基础.蝴蝶兰属、大花蕙兰(Cymbidium hybrdium)、石斛兰属、文心兰属、五唇兰属和万代兰属等兰科植物都有转基因的研究报道,主要以原球茎为材料采用基因枪或农杆菌法转化,部分研究获得了转化植株.     

Superoxide Dismutase Therapy for Myocardial Ischemia

Oxygen derived free radicals have been shown to be generated during reperfusion of ischemic myocardium by a variety of approaches including spin trap probes. Three levels of injury have been described for the reperfused heart. Periods of ischemia of only several minutes can trigger lethal arrhythmias on reperfusion. Anti-oxidants including SOD and or catalase, as well as iron chelators reduce the incidence of these arrhythmias in both dog and rat. Xanthine oxidase inhibitors arc equipotent with SOD in this model suggesting that xanthine oxidase is the source of the radicals. Periods of occlusion lasting 10–15 minutes produce a recoverable defect in contractility termed “stunning”. SOD plus catalase has been shown to reduce the incidence of stunning in a variety of models including the xanthine oxidase deficient rabbit. Neither agent on its own seemed to be effective against stunning in either the rabbit or the dog. Stunning is more difficult to demonstrate in the rabbit heart, presumably due to its lack of xanthine oxidase. Periods of ischemia in excess of 20 minutes will result in some irreversible cell death (infarction) with reperfusion. While studies using histochemical methods suggested that SOD plus Catalase given at the time of reper-fusion could limit necrosis in the dog model, histological studies reveal that infarct size was not modified but rather, SOD appears to interfere with the ability of tetrazoliurn to histochemically discriminate between living and dead cells. While PEG SOD with its extended plasma half life was reported to reduce infarct size in the dog. it was unable to protect the reprefused rabbit heart. To date. none of the scavengers have been proven to limit infarction suggesting that free radicals contribute to arrythmias and stunning, but do not. kill cells in the reperfused heart.     

血红细胞超氧化物歧化酶(SOD)制备工艺的研究初报

本文报告了本实验室设计的由血红细胞自溶液60℃热变性, 乙醇——氯仿法除血红蛋白,旋转蒸发法减压浓缩抽去氯仿、乙醇,硫酸铵分级盐析法沉降SOD,Sepbadex G-75层析提纯SOD等步骤构成的一条成本低、设计合理、简便实用的分离纯化SOD的工艺路线。     

膜分离法纯化大蒜超氧化物歧化酶的条件研究

本文探讨了膜分离技术分离纯化大蒜超氧化物歧化酶(SOD )的工艺条件,研究了中空纤维超滤膜分离提纯大蒜SOD的工艺参数.通过单因素实验,分析了温度、压力、透过率对SOD活力回收率的影响;并通过正交实验确定出超滤膜分离法的最佳条件:温度32 ℃,压力0.15 MPa,透过率90%.在此基础上研究了纳滤膜对超滤液进行浓缩纯化的工艺条件,适宜的纳滤条件为:温度32 ℃,压力1.4 MPa.     

Novel Iron Complexes Behave Like Superoxide Dismutase In Vivo

Novel iron and copper complexes having tris[N-(5-methyl-2-pyridylmethyl)-2-aminoethyl]amine (5MeT-PAA), tris[N-(3-methyl-2-pyridylmethyl)-2-aminoethyl]amine(3MeTPAA),rris[N-(5-methoxycarbonyl-2-pyridylmethyl)-2-aminoethyl]amine (TNAA), tris[(2-thienylmethyI)-2-aminoethyl]amine (TTAA), tris[(2-furylniethyl)-2-aminoethyl]amine (TFAA) or tris[(2-imidazolyl)-2-aminoethyl]amine (TIAA) as ligand. were synthesized to examine the superoxide dismutase (SOD) activity. The concentrations of Fe-3MeTPAA and Fe-TIAA equivalent to 1 unit of SOD (IC₅₀) were 0.5 μM and I.O μM. respectively. Fe-3MeTPAA and Fe-TIAA had higher SOD activity than other Fe and Cu complexes and protected Escherichiu coli cells from paraquat toxicity. In case of using tris[N-(Cmethyl-2-pyridylrnethyl)-2-aminoethyl]amine (6MeTPAA) as ligand, the Fe complex could not be obtained, which may be due to the steric hindrance of Cmethyl substituent. Generally, Cu complexes had low SOD activity, compared with Fe complexes, and could not suppress paraquat toxicity.     

Induction of Superoxide Dismutase by Molecular Oxygen

Oxygen induces superoxide dismutase in Streptococcus faecalis and in Escherichia coli B. S. faecalis grown under 20 atm of O(2) had 16 times more of this enzyme than did anaerobically grown cells. In the case of E. coli, changing the conditions of growth from anaerobic to 5 atm of O(2) caused a 25-fold increase in the level of superoxide dismutase. Induction of this enzyme was a response to O(2) rather than to pressure, since 20 atm of N(2) was without effect. Induction of superoxide dismutase was a rapid process, and half of the maximal level was reached within 90 min after N(2)-grown cells of S. faecalis were exposed to 20 atm of O(2) at 37 C. S. faecalis did not contain perceptible levels of catalase under any of the growth conditions investigated by Stanier, Doudoroff, and Adelberg (23), and the concentration of catalase in E. coli was not affected by the presence of O(2) during growth. S. faecalis, which had been grown under 100% O(2) and which therefore contained an elevated level of superoxide dismutase, was more resistant of 46 atm of O(2) than were cells which had been grown under N(2). E. coli grown under N(2) contained as much superoxide dismutase as did S. faecalis grown under 1 atm of O(2). The E. coli which had been grown under N(2) was as resistant to the deleterious effects of 50 atm of O(2) as was S. faecalis which had been grown under 1 atm of O(2). These results are consistent with the proposal that the peroxide radical is an important agent of the toxicity of oxygen and that superoxide dismutase may be a component of the systems which have been evolved to deal with this potential toxicity.     

微生物产超氧化物歧化酶的研究进展

从产生超氧化物歧化酶 (Superoxidedismutase,EC 1 .1 5 .1 .1 ,简称SOD)的微生物类群及其生理学机理、发酵工艺条件、基因重组菌的研究以及SOD的应用现状等方面 ,对以微生物为原料制备超氧化物歧化酶的研究进展及发展趋势进行了综述。     

伤寒沙门氏菌SOD的提取及抗原性研究

经硫酸铵分级沉淀,ＤＥＡＥ纤维素柱层析提取了伤寒沙门氏菌ＳＯＤ。提取后酶的比活性为３２７０Ｕ／ｍｇ,经聚丙烯酰胺凝胶电泳,蛋白质染色及酶活性染色显示提取的ＳＯＤ达到了电泳纯。酶活性染色法和原子吸收分光光度法测定结果表明提取的ＳＯＤ为Ｆｅ－ＳＯＤ。双向琼脂扩散试验结果显示抗伤寒沙门氏菌Ｆｅ－ＳＯＤ血清与牛红细胞ＳＯＤ不形成沉淀线,提示伤寒沙门氏菌Ｆｅ－ＳＯＤ与牛红细胞ＳＯＤ无交叉反应,抗体对酶活性抑制试验结果显示抗Ｆｅ－ＳＯＤ血清可抑制伤寒沙门氏菌及鼠伤寒沙门氏菌的Ｆｅ－ＳＯＤ和Ｆｅ／Ｍｎ－ＳＯＤ活性,对Ｍｎ－ＳＯＤ活性无抑制作用,说明伤寒沙门氏菌和鼠伤寒沙门氏菌的ＳＯＤ之间有共同抗原,也提示ＳＯＤ的辅基似乎决定了其抗原特异性。     

Enhanced Electron Transfer by Unsaturated Fatty Acids and Superoxide Dismutase

We have previously shown that unsaturated fatty acids (UFA) facilitate electron transfer between iron centers such as ferrous iron and ferricytochrome C. Extending this concept to a more physiologic model of fatty acids associated with proteins, we find that electron transfer is also enhanced in this model. While investigating whether free superoxide was involved in this electron transfer, we discovered that superoxide dismutase (SOD) enchanced the electron transfer. While the mechanism of electron transfer is unknown, the above findings are consistent with UFA and SOD participating in membrane redox systems.     

Effects of Liposomal Superoxide Dismutase on Human Neutrophil Activity

Study of the effects of liposomal bovine copper superoxide dismutase on human polymorphonuclear neutrophils with respect to production of active oxygen species, chemotaxis and random migration, or bacterial killing show that no significant interference with neutrophil function is observed at levels far exceeding the clinical doses used in the treatment of various pathologies.     

Preparation of Long-Acting Superoxide Dismutase Using High Molecular Weight Polyethylene Glycol (41,000-72,000 Daltons)

Superoxide dismutase (SOD) has demonstrated therapeutic potential for treating a variety of conditions including radiation injury, oxygen toxicity, reperfusion injury, and inflammation, especially arthritis. However, the native enzyme's short half-life in plasma (6 minutes in mice. 25 minutes in man) limits the enzyme's effectiveness in many applications, or requires infusion of large doses. High doses of SOD derived from either natural or rDNA sources may increase the potential for immunologic sensitization. One effective use of native SOD is intra particular administration for treatment of arthritis, where injection of SOD into joints retards elimination (15 hour terminal half-life), allowing the effective use of lower doses.

To overcome the limitations resulting from rapid clearance. various researchers have increased the persistence of SOD by cross-linking SOD or by attaching polymeric substances, including dextrans, albumin, Ficoll, polyvinyl alcohol or polyethylene glycol (PEG). PEG is relatively safe; however. the amount of modification by PEG. is the MW range 1.900-5.000 daltons, which is necessary to optimally increase serum persistence and reduce immunogenicity, results in the loss of much of the enzymatic activity.

In this report we describe the preparation of SOD adducts containing I to 4 strands of high MW PEG (41,000-72,000 daltons). The MW range of these adducts, measured by steric exclusion HPLC based on protein standards, is 200,000 to over 1,100,000 daltons. The number of PEG strands attached per SOD dimer (32,000 daltons) was measured by HPLC. Because of the low degree of protein modification required to produce very high MW products, these PEG-SODS retain 90%-100% of the SOD activity of the native enzyme. Additionally, these very large adducts demonstrate longer persistence and lower immunogenicity and antigenicity compared to the more highly modified PEG-SODS containing low MW PEG (i.e., 7-16 strands of 5.000 dalton methoxy-PEG).