Temporal relationship of free radical-induced lipid peroxidation and loss of latent enzyme activity in highly enriched hepatic lysosomes.
Temporal relationship of free radical-induced lipid peroxidation and loss of latent enzyme activity in highly enriched hepatic lysosomes.
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DOI：
10.1016/s0021-9258(17)43979-2
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发表时间：
1983-11
期刊：
影响因子：
--
通讯作者：
I. Mak;H. Misra;W. Weglicki
中科院分区：
文献类型：
--
作者：
I. Mak;H. Misra;W. Weglicki
在高纯度大鼠肝脏溶酶体中，研究了体外诱导的膜脂质过氧化引起的潜伏期损失。用自由流动电泳法分离溶酶体富集组分。溶酶体的脂质过氧化反应是由二羟基富马酸和Fe3+-ADP组成的自由基生成体系催化的。过氧化反应在37℃时很容易发生，在10分钟时达到平台期；然而，溶酶体潜伏期的丧失(确定为游离β-N-乙酰氨基葡萄糖苷酶活性增加的百分比)发生得更缓慢，并在30分钟后达到最大。超氧化物、过氧化氢、单线态氧和羟基自由基的清除剂不能抑制过氧化反应，也不能阻止溶酶体潜伏期的丧失。然而，溶酶体与α-生育酚预先孵育有效地阻止了过氧化的诱导，并显著减少了溶酶体潜伏期的损失。这些结果表明，溶酶体膜对自由基诱导的脂质过氧化反应敏感，这一过程可能是随后溶酶体解体的直接原因。α-生育酚的保护作用的本质尚不清楚，但可能是由于其与不饱和膜脂的相互作用以及随后由自由基引发的链式反应的中断。
Loss of latency due to membrane lipid peroxidation induced in vitro was studied in highly purified rat liver lysosomes. Enriched fractions of lysosomes were isolated by free flow electrophoresis. Lipid peroxidation of lysosomes, assayed as malondialdehyde formation, was catalyzed by a radical generating system consisting of dihydroxyfumaric acid and Fe3+-ADP. The peroxidation reaction occurred readily at 37 degrees C and reached a plateau at 10 min; however, the loss of lysosomal latency, determined as increased percentage free beta-N-acetylglucosaminidase activity, occurred more gradually and reached a maximum after 30 min. Scavengers of superoxide, hydrogen peroxide, singlet oxygen, and hydroxyl radicals did not inhibit the peroxidation reaction nor prevent the loss of lysosomal latency. However, preincubation of the lysosomes with alpha-tocopherol effectively blocked the induction of peroxidation and substantially reduced the loss of lysosomal latency. These results indicate that the lysosomal membrane is susceptible to free radical-induced lipid peroxidation; further, this process may be the immediate cause of the subsequent disintegration of the lysosome. The nature of the protective effect of alpha-tocopherol is unclear but may be due to its interaction with the unsaturated membrane lipids and the subsequent interruption of the chain-reaction initiated by free radicals.