Determination of the α-tocopherol inhibition rate constant for peroxidation in low-density lipoprotein
Determination of the α-tocopherol inhibition rate constant for peroxidation in low-density lipoprotein
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DOI：
10.1021/tx020012t
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发表时间：
2002-06-01
影响因子：
4.1
通讯作者：
Porter, NA
中科院分区：
文献类型：
--
作者：
Culbertson, SM;Antunes, F;Porter, NA
这项工作报告了基于完整脂蛋白自氧化过程中形成的胆固醇亚油酸酯氢过氧化物产物对低密度脂蛋白 (LDL) 中α-生育酚 (α-TOH) 的抑制率常数的估计（提示）。在抗氧化剂消耗过程中测定顺式、反式/反式、反式产物氢过氧化物的比率。为了合理确定 LDL 中的 k(inh)，通过使用不对称两亲偶氮引发剂氧化 LDL，显着降低 α-TOH 的相转移介导的促氧化作用，从而最大限度地减少 α-TOH 的促氧化行为。该引发剂将更恒定的引发剂自由基通量输送到 LDL 脂质区域，并允许测定 LDL 中的 α-TOH k(inh)。生育酚介导的过氧化 (TMP) 模型的开发和胆固醇亚油酸酯氢过氧化物顺式、反式/反式、反式产物比率的分析提供了脂蛋白中 α-TOH 的抑制速率常数的估计值 k(inh) = 5.9 +/- 0.5 x 10(5) M-1 s(-1)。
This work reports an estimate of the inhibition rate constant (hint,) for a-tocopherol (alpha-TOH) in low-density lipoproteins (LDL) based on cholesteryl linoleate hydroperoxide products formed during autoxidation of intact lipoproteins. The ratio of cis,trans/trans,trans product hydroperoxides was determined during the consumption of the antioxidant. For a reasonable determination of k(inh) in LDL, the pro-oxidant behavior of alpha-TOH was minimized by oxidizing LDL with an unsymmetrical amphiphilic azo initiator which significantly reduces phase-transfer mediated pro-oxidant effects of alpha-TOH. This initiator delivers a more constant flux of initiator radicals into LDL lipid regions and permits determination of alpha-TOH k(inh) in LDL. Development of a tocopherol-mediated peroxidation (TMP) model and analysis of cholesteryl linoleate hydroperoxide cis,trans/trans,trans product ratios provided an estimated value for the inhibition rate constant of alpha-TOH in a lipoprotein of k(inh) = 5.9 +/- 0.5 x 10(5) M-1 s(-1).