O'Leary V J, Darley-Usmar V M, Russell L J, Stone D
Biochemical Sciences, Wellcome Research Laboratories, Beckenham, Kent, U.K.
Biochem J. 1992 Mar 15;282 ( Pt 3)(Pt 3):631-4. doi: 10.1042/bj2820631.
It has been proposed that lipoxygenases, specifically 15-lipoxygenase, may play an important role in promoting the oxidation of low-density lipoprotein (LDL) in the artery wall. It is well known that peroxides are unstable in the presence of transition metals, decomposing to form the alkoxy and peroxy radicals, and so initiating lipid peroxidation. To test whether lipoxygenase-derived peroxides may promote the oxidation of LDL in the presence of copper, the lipoprotein was enriched with lipid peroxides derived from the enzymic action of 5- and 15-lipoxygenases on either linoleic or arachidonic acid. All of these products were found to promote oxidation, whereas the related hydroxy fatty acids had no effect. This suggests that lipoxygenase-derived peroxides associated with the LDL particle may promote peroxidation in the presence of a suitable transition metal catalyst. This result has implications both for the mechanism of the potential pro-oxidant action of lipoxygenases in vivo and for the ex vivo assessment of the oxidizability of LDL samples isolated from different donors.
有人提出，脂氧合酶，特别是15-脂氧合酶，可能在促进动脉壁中低密度脂蛋白（LDL）的氧化过程中发挥重要作用。众所周知，过氧化物在过渡金属存在下不稳定，会分解形成烷氧基和过氧自由基，从而引发脂质过氧化。为了测试脂氧合酶衍生的过氧化物在铜存在下是否会促进LDL的氧化，该脂蛋白用5-和15-脂氧合酶对亚油酸或花生四烯酸的酶促作用产生的脂质过氧化物进行了富集。所有这些产物都被发现能促进氧化，而相关的羟基脂肪酸则没有效果。这表明与LDL颗粒相关的脂氧合酶衍生的过氧化物在合适的过渡金属催化剂存在下可能会促进过氧化。这一结果对于脂氧合酶在体内潜在促氧化作用的机制以及对从不同供体分离的LDL样品氧化能力的体外评估都具有重要意义。
