Inhibition of superoxide and ferritin-dependent lipid peroxidation by ceruloplasmin.
Inhibition of superoxide and ferritin-dependent lipid peroxidation by ceruloplasmin.
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发表时间：
1989-01
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通讯作者：
V. Samokyszyn;D. Miller;D. Reif;S. Aust
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作者：
V. Samokyszyn;D. Miller;D. Reif;S. Aust
研究发现，铜蓝蛋白 (CP) 可以抑制黄嘌呤氧化酶和铁蛋白依赖性磷脂脂质体过氧化反应，丙二醛形成减少就证明了这一点。使用铁 (II) 螯合剂红菲绕啉磺酸盐进行分光光度法测量，铜蓝蛋白还可以以浓度依赖性方式抑制超氧化物介导的铁蛋白中铁的动员。铜蓝蛋白未能发挥过氧自由基清除抗氧化剂的作用，其无法抑制自由基引发的亚油酸过氧化反应，表明铜蓝蛋白通过影响铁蛋白衍生铁的利用率来抑制脂质过氧化。此外，通过分光光度法通过其对细胞色素 c 还原的影响来测量，CP 清除了黄嘌呤氧化酶衍生的超氧化物。然而，CP清除超氧化物的程度并不能定量地解释其对铁释放的影响，这表明CP抑制铁蛋白铁的超氧化物依赖性动员，与其清除超氧化物的能力无关。还研究了 CP 和脱铁铁蛋白对含有外源添加亚铁的系统中铁催化的脂质过氧化的影响。在没有脱铁铁蛋白的情况下，CP 表现出浓度依赖性的促氧化作用。然而，添加脱铁铁蛋白可抑制 CP 依赖性、铁催化的脂质过氧化作用。脱铁铁蛋白不具有清除过氧自由基的抗氧化剂的作用，但在 CP 存在的情况下会结合铁。这些数据表明，CP 抑制超氧化物和铁蛋白依赖性脂质过氧化，主要是通过其将还原动员的铁重新结合回铁蛋白的能力。
Ceruloplasmin (CP) was found to inhibit xanthine oxidase and ferritin-dependent peroxidation of phospholipid liposomes, as evidenced by decreased malondialdehyde formation. Ceruloplasmin was also shown to inhibit superoxide-mediated mobilization of iron from ferritin, in a concentration-dependent manner, as measured spectrophotometrically using the iron(II) chelator bathophenanthroline sulfonate. Ceruloplasmin failed to function as a peroxyl radical-scavenging antioxidant as evidenced by its inability to inhibit free radical-initiated peroxidation of linoleic acid, suggesting that CP inhibited lipid peroxidation by affecting the availability of ferritin-derived iron. In addition, CP scavenged xanthine oxidase-derived superoxide as measured spectrophotometrically via its effect on cytochrome c reduction. However, the extent of the superoxide scavenging of CP did not quantitatively account for its effects on iron release, suggesting that CP inhibits superoxide-dependent mobilization of ferritin iron independently of its ability to scavenge superoxide. The effects of CP and apoferritin on iron-catalyzed lipid peroxidation in systems containing exogenously added ferrous iron was also investigated. In the absence of apoferritin, CP exhibited a concentration-dependent prooxidant effect. However, CP-dependent, iron-catalyzed lipid peroxidation was inhibited by the addition of apoferritin. Apoferritin did not function as a peroxyl radical-scavenging antioxidant but was shown to incorporate iron in the presence of CP. These data suggest that CP inhibits superoxide and ferritin-dependent lipid peroxidation largely via its ability to reincorporate reductively mobilized iron back into ferritin.