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Nafion膜固定的麦尔多拉蓝为介体的过氧化氢、葡萄糖和乳糖生物传感器 总被引:8,自引:4,他引:8
以Nafion膜修饰玻碳电极固定的麦尔多拉蓝为辣根过氧化物酶和电极间的电子传递介体,成功地制成了性能优良的电流型单酶过氧化氢生物传感器;在此基础上通过固定双酶(辣根过氧化物酶-葡萄糖氧化酶)和三酶(辣根过氧化物酶-葡萄糖氧化酶-半乳糖苷酶)分别制成了葡萄糖和乳糖生物传感器;探讨了工作电位、pH、温度和干扰物质等对这3种生物传感器的影响。 相似文献
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本文通过β-环糊精与环氧氯丙烷反应,合成了交联预聚物,进而在酸性条件下与戊二醛和辣根过氧化物酶反应,从而把辣根过氧化物酶固定在所形成的聚合物绝缘体基底上.应用扫描电化学显微镜的反馈模式,研究了辣根过氧化物酶的催化反应动力学.通过对扫描电化学显微镜在酶点上的反馈曲线与理论曲线的拟合,测得了一级反应速率常数,并用此方法研究了pH对反应速率常数的影响.在pH=7.0时,辣根过氧化物酶的活性最高,与文献报道一致,结果满意. 相似文献
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颜世铭 《广东微量元素科学》2008,(4)
过氧化物,如双氧水,它的化学名称为过氧化氢,化学式是H2O2。它比水多了一个氧原子,所以很不稳定,氧化能力很强。医院外科使用稀的双氧水清洗伤口,就是利用它的氧化能力,清除腐败的皮、肉并起杀菌消毒作用。高含量的双氧水则可烧伤人的皮肤和肌肉。应用兽骨做工艺品时,也往往在兽骨上涂双氧水使兽骨变白,这也是利用双氧水的氧化作用。在自然界和人的身体内存在一种称作自由基的化学物质,如超氧阴离子自由基(O2-),有机过氧基(ROO·),羟自由基(HO·)。这些自由基很不稳定,可对细胞造成氧化损伤。更严重的是,自由基可引发自由基反应。自由基反应是循环式连锁反应。每循环一次都会产生过氧化物,如过氧化氢(H2O2)和不饱和氢过氧化物(ROOH)。这些过氧化物也很不稳定,具有很强的氧化作用,可对DNA、RNA、线粒体膜、内质肉膜、细胞膜造成过氧化损伤。自由基学说的倡导者认为,自由基和自由基反应产生的过氧化物所造成的过氧化损伤是导致衰老和老年多发病,如肿瘤、心脑血管疾病和骨、关节疾患的基本原因。自由基广泛存在于自然界,如受污染并经紫外线照射(阳光照射)的空气、香烟烟雾、熏制食品中,各种生物体内无所不在。在人体内,自由基反应每时每刻都在... 相似文献
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利用对辣根过氧化物酶催化体系的干扰测定左旋多巴 总被引:5,自引:2,他引:3
提出辣根过氧化物酶法分析左旋多巴,方法基于一定条件下左旋多巴对辣根过氧化物酶催化对氯苯酚-4-AAP偶联发色体系有干扰,干扰程度与左旋多巴的有浓度有相关性。 相似文献
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Guangyin Zhou Wen Jiang Yan Zhao Guang-En Ma Shengguang Li Wenjuan Xin Baolu Zhao 《Research on Chemical Intermediates》2002,28(4):277-289
Adriamycin (ADR) is a powerful and widely used antitumor drug, but its dose dependent cardiotoxicity limits its application. This side effect is believed to be caused by the adriamycin semiquinone free radical (ASFR). The primary focus of this work is to test effects of sodium tanshinone IIA sulfonate (STS) on ASFR and adriamycin–induced lipid peroxidation. It was found that ADR, whether in the system of heart homogenate, heart mitochondria or heart submitochondria, with NADH as the substrate or in xanthine/xanthine oxidase under anaerobic conditions, all produced ASFR rapidly. STS was shown to effectively scavenge ASFR in all these systems and postpone the appearance of ASFR. The delayed time was proportional to the amount of STS. Under aerobic conditions, ASFR could be oxidized to generate oxygen free radicals. STS could not scavenge these oxygen free radicals, but it could effectively scavenge lipid free radicals generated from membrane lipid peroxidation of heart mitochondria. STS could significantly reduce mitochondrial swelling and lipid peroxidation induced by ADR. Animal experiments show that treatment of STS could inhibit endogenous lipid peroxidation caused by ADR. Here, a protective mechanism of STS is suggested that STS can rapidly and univalently oxidize ASFR, causing the cycle of adriamycin between its quinone form and semiquinone form and inhibiting the accumulation of ASFR. Under aerobic condition, STS can protect heart mitochondria by scavenging lipid free radicals generated from adriamycin-induced mitochondrial lipid peroxidation. This investigation shows that STS may be a physiological drug to antagonize the cardiotoxicity of ADR. 相似文献
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To treat leaf discs with solutions of various osmotic potentials of polyethylene glycols (MW 6000) by adopting the floating treatment could increase the membrane permeability, decrease the formation of malondialdehyde,and reduce the activity of peroxidase. Nevertheless, the activities of superoxide dismutase and catalase were not obviously altered. In verifying if the membrane damage was caused by lipid peroxidation initiated by active oxygen species, diethyldithiocarbamate was chosen as inhibitor superoxide dismutase,aminotriazole as catalase and mannitol as scavenger of hydroxyl free radicals.The results have shown that there is not any correlation between lipid peroxidation and membrane damage.Therefore,membrane damage caused by water stress is probably not due to free radical initiation. 相似文献
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K. Shridhara Alva Kenneth A. Marx Jayant Kumar Sukant K. Tripathy 《Macromolecular rapid communications》1997,18(2):133-137
Horseradish peroxidase catalyzed polymerization of 8-hydroxyquinoline-5-sulfonate (HQS) has been studied by in-situ NMR spectroscopy. The 2, 4 and 7 positions of the HQS are involved in oxidative free radical coupling with other HQS molecules with the order of reactivity being 7 ≥ 2 > 4. A mechanism for the oxidative free radical coupling and structure of the resulting polymer is proposed, which is supported by 13C NMR spectroscopy. 相似文献
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Baolu Zhao Weiai Zhou Ming Li Yucheng Ni Jingwu Hou Tianli Gao Wenjuan Xin 《Research on Chemical Intermediates》2000,26(7-8):747-762
The kinetic scavenging effect of chinonin on NO and oxygen free radicals generated from ischemia reperfusion myocardium and its protective effect on the myocardium were studied by electron spin resonance (ESR) spin trapping technique. It was found that after 20 minutes ischemia, the first peak of oxygen free radical appeared at about 0.5 minutes after the beginning of reperfusion, then the release of oxygen free radicals decreased with time. The second peak appeared at about 3 minutes. Similarly, there were two peaks of creatine kinase (CK) release, which indicated the myocardial damage, the first one appeared concomitantly with the first oxygen free radical peak but the second one appeared later about 1 minute after appearance of the second peak of oxygen free radicals. The release of NO free radicals was not significant in the absence of L-arginine. However, it increased significantly in the presence of L-arginine and it also possesses a biphase profile. It could protect the ischemia-reperfusion damage in the presence of low concentration of L-arginine (0.1 mM), but in high L-arginine concentration (10 mM) it generated higher concentrations of NO leading to a more serious ischemia-reperfusion damage. Addition of chinonin could scavenge the free radicals and protect the ischemia-reperfusion injury, especially in the second phase. The reduction stoichiometry of chinonin for Fe(III) was measured. 相似文献
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K. Shridhara Alva Kenneth A. Marx Jayant Kumar Sukant K. Tripathy 《Macromolecular rapid communications》1996,17(12):859-863
This report describes the synthesis of a water soluble polyaniline through a biochemical synthetic route. The oxidative free radical coupling mechanism for the synthesis of poly(p-aminobenzoic acid) is catalyzed by horseradish peroxidase in the presence of hydrogen peroxide. The resulting polymer is electrochemically active and undergoes reversible redox reactions. The polymer as synthesized is self doped and undergoes undoping in alkaline or ammonia solutions. 相似文献
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研究鸡足山耳蕨中总黄酮的提取及其抗氧化性.采用70%乙醇提取鸡足山耳蕨中总黄酮,用NaNO2Al(NO3)3-NaOH分光光度法测定黄酮含量,将提取液采用Fenton体系、普鲁士蓝法进行体外抗氧化活性研究,用硫代巴比妥酸(TBA)分光光度法研究其对羟自由基·OH引发DNA氧化损伤的抑制作用.结果表明样品中总黄酮含量为4.98%,回收率99.78%( RSD=1.06%,n=5).总黄酮浓度为90μg/mL时,对·OH的清除率可达36.2%;浓度为87.5μg/mL时,对羟自由基引发DNA损伤的抑制率可达93.0%.说明鸡足山蕨中总黄酮对羟自由基有较好的清除能力,对DNA氧化损伤有显著抑制作用. 相似文献
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目的观察番茄红素对镉诱导睾丸损伤大鼠抗氧化酶活性及生殖激素水平的影响。方法将28只雄性SD大鼠随机分为4组,每组7只,分别为空白对照组、5 mg/L镉组、5 mg/L镉+10 mg/kg番茄红素组、5 mg/L镉+20 mg/kg番茄红素组,给药1周后处死,测定睾丸组织超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)活性及血清促黄体生成素(LH)、睾酮(T)水平。结果镉组大鼠体质量、睾丸质量、睾丸组织SOD、GSH-Px活性及血清T水平均显著低于NC组(P0.01),睾丸组织MDA含量和血清LH水平则显著高于后者(P0.01);番茄红素可缓解染镉大鼠体质量和睾丸质量的减轻,并回调抗氧化酶活性和生殖激素水平,且高剂量组效果更为显著。结论番茄红素对染镉大鼠的睾丸损伤具有剂量依赖性的改善作用,可能与清除氧自由基和抗脂质过氧化有关。 相似文献
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Kadiiska MB Mason RP 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(6):1227-1239
Copper has been suggested to facilitate oxidative tissue injury through a free radical-mediated pathway analogous to the Fenton reaction. By applying the electron spin resonance (ESR) spin-trapping technique, evidence for hydroxyl radical formation in vivo was obtained in rats treated simultaneously with copper and ascorbic acid or paraquat. A secondary radical spin-trapping technique was used in which the hydroxyl radical formed the methyl radical upon reaction with dimethylsulfoxide. The methyl radical was then detected by ESR spectroscopy as its adduct with the spin trap phenyl-N-t-butyl- nitrone (PBN). In contrast, lipid derived radical was detected in vivo in copper-challenged, vitamin E and selenium-deficient rats. These findings support the proposal that dietary selenium and vitamin E can protect against lipid peroxidation and copper toxicity. Since copper excreted into the bile from treated animals is expected to be maintained in the Cu(I) state (by ascorbic acid or glutathione), a chelating agent that would redox-stablilize it in the Cu(I) state was used to prevent ex vivo redox chemistry. Bile samples were collected directly into solutions of bathocuproinedisulfonic acid, a Cu(I)-stabilizing agent, and 2,2'-dipyridyl, a Fe(II)-stabilizing agent. If these precautions were not taken, radical adducts generated ex vivo could be mistaken for radical adducts produced in vivo and excreted into the bile. 相似文献
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硒是人体必需微量元素,它参与抗氧化酶谷胱甘肽过氧化物酶和多种硒蛋白的组成,在体内发挥消除自由基、抗氧化物等作用。硒的抗衰老与抑制肿瘤细胞生长的作用是通过它对端粒酶的作用而实现的。研究端粒酶的调控及其与细胞凋亡的关系已成为人类种瘤研究的新热点。 相似文献
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N E Saris I A Skulskii 《Acta chemica Scandinavica (Copenhagen, Denmark : 1989)》1991,45(10):1042-1046
The uptake of Cu+ by rat liver mitochondria is rapid and extensive. Respiration is stimulated by 10 microM Cu+ then inhibited and the inhibition could not be relieved with uncoupling agents. Collapse of the membrane potential is induced by 5-10 microM Cu+. These effects are partially inhibited by radical scavengers indicating the involvement of radical production in these events. Reduction of the GSH content and production of peroxidation products by higher amounts of Cu+ was also demonstrated. Swelling of non-respiring rat liver and heart mitochondria in sodium or lithium acetate was used to study effects of Cu+ on the Na+/H+ exchanger. Swelling is stimulated by 5-100 microM Cu+. In the presence of a radical scavenger the swelling is reduced. In sodium nitrate media diltiazem-sensitive stimulated swelling is observed. Amiloride was found to inhibit Cu(+)-induced efflux of Ca2+. At high concentrations of Cu+, a general increase in permeability was the dominant feature. 相似文献