LIPID PEROXIDATION

大约25年前，霍奇森和弗里多维奇报告说，铜 锌超氧化物歧化酶混合物能够催化 不饱和脂肪的过氧化。氧化剂负责 脂质的氧化被认为是铜结合的羟基。 激进的。为了更好地了解超氧化物歧化酶的催化机理 为了防止脂质过氧化，我们用S-亚硝基谷胱甘肽(GSnO)作为一种 抗氧化剂探针。在孵化过程中加入过氧化氢(1 MM) 含有大豆磷脂酰胆碱脂质体的混合物(250 微克/毫升)和超氧化物歧化酶(200微克/毫升)引起的 共轭二烯的形成被添加的抑制 二乙烯三胺五乙酸(DTPA)。添加GSNO(10-50 Microm)导致时间延迟随浓度的增加而增加 共轭二烯的形成表明GSNO是作为硝基 这个系统中的氧化物供体。GSNO在体内释放的一氧化氮 用化学发光法检测超氧化物歧化酶和过氧化氢的存在。我们是 但超氧化物歧化酶和过氧化氢引起的过氧化作用增加 从超氧化物歧化酶释放的铜离子随后催化 脂质过氧化氢依赖的氧化。目前的结果 证明一氧化氮是一种极好的断链方法 抗氧化剂。GSNO的抗氧化活性归因于 铜离子依赖的一氧化氮的释放，起到链的作用 破坏抗氧化剂。目前的结果还表明， 亚硝硫醇中的谷氨酸基团使它们不太容易受到影响 到铜催化的分解。

Nearly 25 years ago, Hodgson and Fridovich reported that copper zinc superoxide dismutase mixture was able to catalyze the peroxidation of unsaturated lipids. The oxidant responsible for oxidation of lipid was suggested to be a copper-bound hydroxyl radical. To better understand the mechanism of SOD peroxide catalyzed lipid peroxidation, we have used S-nitrosoglutathione (GSNO) as an antioxidant probe. Addition of peroxide (1 mM) to an incubation mixture containing soybean phosphatidylcholine liposomes (250 microg/ml) and SOD (200 micro g/ml) caused an increase in the formation of conjugate diene which was inhibited by the addition of diethylenetriaminepentaacetic acid (DTPA). Addition of GSNO (10-50 microM) caused a concentration-dependent increase in time-lag for conjugate diene formation indicating that GSNO is acting as a nitric oxide donor in this system. Nitric oxide released from GSNO in the presence of SOD and peroxide was measured by chemiluminescence. We a ttri bute the increase in peroxidation caused by SOD and peroxide to the copper ions released from SOD that subsequently catalyzes the lipid hydroperoxide-dependent oxidation. The present results demonstrate the nitric oxide is an excellent chain-breaking antioxidant. The antioxidant activity of GSNO is attributed to the copper ion dependent release of nitric oxide, which acts as a chain breaking antioxidant. The present results also show that the glutamate groups present in nitrosothiols make them less susceptible to copper-catalyzed decomposition.