谷胱甘肽和二氧化锰的氧化还原反应在生物领域上的应用

谷胱甘肽(GSH)是一种普遍存在的生物硫醇,具有清除毒素、维持氧化还原稳态和调控基因的作用,GSH的异常水平可能是多种疾病的触发因素.过渡金属氧化物二氧化锰(MnO_2)具有很强的氧化能力,能被GSH还原为Mn~(2+),可用于磁共振成像(MRI)以及肿瘤治疗.GSH和MnO_2之间的氧化还原反应已成为科研工作者不断研究和探索的方向.综述了GSH和MnO_2的氧化还原反应的最新研究进展.     

The effects of vitamin A nutritional status on glutathione,glutathione transferase and glutathione peroxidase activities in rat intestine

Summary In rat intestine, the glutathione level was increased, glutathione peroxidase activity decreased and glutathione-S-transferase unchanged by vitamin A deficiency.     

Melatonin regulation of antioxidant enzyme gene expression

Antioxidant enzymes (AOEs) are part of the primary cellular defense against free radicals induced by toxins and/or spontaneously formed in cells. Melatonin (MLT) has received much attention in recent years due to its direct free radical scavenging and antioxidant properties. In the present work we report that MLT, at physiological serum concentrations (≈ 1 nM), increases the mRNA of both superoxide dismutases (SODs) and glutathione peroxidase (GPx) in two neuronal cell lines. The MLT effect on both SODs and GPx mRNA was mediated by a de novo synthesized protein. MLT alters mRNA stability for Cu-Zn SOD and GPx. Experiments with a short time treatment (pulse action) of MLT suggest that the regulation of AOE gene expression is likely to be receptor mediated, because 1-h treatment with MLT results in the same response as a 24-h treatment. Received 18 June 2002; received after revision 5 August 2002; accepted 27 August 2002 RID="*" ID="*"Corresponding author.     

Peroxovanadate inhibits Ca2+ release from mitochondria

Mitochondria contain a specific Ca²⁺ release pathway which operates when oxidized mitochondrial pyridine nucleotides are hydrolyzed. NAD⁺ hydrolysis and therefore Ca²⁺ release is possible when some vicinal thiols are cross-linked. Here we report that the thiol oxidant peroxovanadate inhibits the specific Ca²⁺ release pathway. In mitochondria, peroxovanadate causes a complete loss of reduced glutathione, which is not accompanied by formation of glutathione disulfide, and a partial loss of protein thiols. In model reactions, peroxovanadate oxidizes reduced glutathione predominantly to the sulfonate derivative, but does not react with glutathione disulfide. When the vicinal thiols relevant for Ca²⁺ release are cross-linked, Ca²⁺ release is no longer inhibited by peroxovanadate. Conversely, pretreatment of mitochondria with peroxovanadate makes them insensitive to compounds promoting the disulfide state. These results suggest that peroxovanadate inhibits the prooxidant-induced Ca²⁺ release from mitochondria by (i) depleting mitochondria of reduced glutathione and (ii) oxidizing the vicinal thiols relevant for Ca²⁺ release to a state higher than disulfide, presumably the sulfonate state. The findings provide further insight into the regulation of Ca²⁺ release from intact mitochondria, and may be relevant for a better understanding of the action of peroxovanadate in cells, where the compound can be insulin mimetic. Received 28 March 2002; received after revision 8 May 2002; accepted 15 May 2002     

谷胱甘肽S—转移酶5—5和细菌二氯甲烷脱卤素酶的性质比较

通过简便的两步阴离子交换色谱，从遗传工程菌株大肠杆菌ＪＭ１０５中纯化出哺乳动物的谷胱甘肽Ｓ－转移酶５－５（ＧＳＴ５－５），ＧＳＴ５－５以二卤甲烷为底物时的动力学常数，热稳定性和最适ｐＨ被测定，并与细菌二氯甲烷脱卤素酶的上述性质进行了比较。     

珍珠口服液的抗衰老功能评价

以１０月龄ＢＡＬＢ／Ｃ雄性小鼠为实验对象，研究珍珠口服液对衰老指标的影响，结果表明：与对照组相比，珍珠口服液使脑Ｂ型单胺氧化酶比活性下降１８９９％（Ｐ＜０００１）；红细胞谷胱甘肽过氧化物酶活性升高１８８３％（Ｐ＜０００１）；心肌脂褐素含量下降２４３３％（Ｐ＜００１），表明珍珠口服液具有一定的延缓衰老的作用。     

麻风病人血液超氧化物歧化酶和谷胱甘肽过氧化物酶活性测定分析

人体内的超氧化物歧化酶（ＳＯＤ）和谷胱甘肽过氧化物酶（ＧＳＨ－ＰＸ）．是清除和ＯＨ、ＲＯＯＨ等自由基的主要酶．通过测定正常人、麻风病人的血液ＳＯＤ、ＧＳＨ－ＰＸ活性．探讨麻风病人血液ＳＯＤ、ＧＳＨ－ＰＸ变化对自由基清除的影响．结果显示：麻风病人体内的ＳＯＤ和ＧＳＨ－ＰＸ活性显著低于正常人（Ｐ＜０．０１）；而现症和治愈、多菌型和少菌型、活动期和消退期病人之间无显著性差异（Ｐ＞０．０５）．提示ＳＯＤ和ＧＳＨ－ＰＸ活性降低与麻风杆菌感染有关．且感染麻风菌后病人治愈前后血液中的ＳＯＤ和ＧＳＨ－ＰＸ活性没有明显变化．     

Tissue-specific expression of glutathione S-transferases induced by 2-tridecanone or quercetin in cotton bollworms, Helicoverpa armigera (Hübner)

The tissue-specific expression of glutathione S-transferases (GSTs) in the cotton bollworm and the expression level induced by 2-tridecanone and quercetin were examined using the methods of biochemistry and the quantitative PCR. The relative expression level of GST mRNA was unanimous with the GSTs activity conjugaging with 1-chloro-2, 4-dimitro-benzene (CDNB) in fat bodies,midguts, heads and integuments of cotton bollworms. The GSTs activity in fat bodies was the highest, then midguts, heads and integuments in turn, which was in consistent with the relative expression level of GST mRNA. The specific activity of GSTs and the relative expression level of GST mRNA could be significantly induced by 2-tridecanone and quercetin, and after the induction the order of the GSTs activity and the relative expression level of GST mRNA in the above four tissues in cotton bollworms was not different from the control.The induction of GSTs by 2-tridecanone was stronger than by quercetin in all four tissues, which was in accordance with the relative expression level of GST mRNA. It suggested that the increase of GSTs activity induced by plant allelochemicals was associated with the elevated expression of GST mRNA in cotton bollworms.     

苯并芘,芘及其混合物暴露对梭鱼肝脏还原型谷胱甘肽质量分数的影响

在实验生态条件下，研究质量浓度从0.1-50μg/L的苯并（a）芘，芘及其等质量浓度混合物暴露后对梭鱼（Mugil so-iuy）肝脏还原型谷胱甘肽质量分数的影响。结果显示，对肝脏还原型谷胱甘肽质量分数影响表现出诱导效应。存在较好的质量浓度－效应关系，质量浓度比为1：1的苯并（a）芘和芘对还原型谷胱甘肽质量分数的联合效应为拮抗作用。     

富硒蚯蚓含硒蛋白研究

蚯蚓作为药用在我国已有二千多年历史。李时珍的“本草纲目”以蚯蚓配伍的药方就有40多种,用蚓粪配伍的药亦有21种。蚯吲和蚓粪也可作为兽药,治疗猪气管炎、仔猪白痢。此外,欧洲出版的百科全书也有蚯蚓作药的记载。近十年来经过毒性试验表明蚯蚓无毒和无副作用。蚯蚓体腔液中认含有人体必需氨基酸和特殊的酶,食后能促进皮肤新陈代谢,变得细嫩并富弹性。