Unusual kinetic isotope effects of deuterium reinforced polyunsaturated fatty acids in tocopherol-mediated free radical chain oxidations.
Unusual kinetic isotope effects of deuterium reinforced polyunsaturated fatty acids in tocopherol-mediated free radical chain oxidations.
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DOI：
10.1021/ja410569g
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发表时间：
2014-01-22
影响因子：
15
通讯作者：
Porter NA
中科院分区：
文献类型：
--
作者：
Lamberson CR;Xu L;Muchalski H;Montenegro-Burke JR;Shmanai VV;Bekish AV;McLean JA;Clarke CF;Shchepinov MS;Porter NA
取代-CD 2-在亚油酸和亚麻酸的反应中心的D的提取率降低生育酚自由基高达36倍，从相应的-CH 2-中心的H的提取相比。这种氢原子转移反应是生育酚介导的人类低密度脂蛋白脂质过氧化反应的速率决定步骤，这一过程与冠状动脉疾病有关。这里报道的生育酚介导的亚油酸和亚麻酸及其酯的氧化的未预料到的大的动力学同位素效应表明，隧穿使该过程有利。
Substitution of –CD2– at the reactive centers of linoleic and linolenic acids reduces the rate of abstraction of D by a tocopheryl radical by as much as 36-fold, compared to the abstraction of H from a corresponding –CH2– center. This H atom transfer reaction is the rate-determining step in the tocopherol-mediated peroxidation of lipids in human low-density lipoproteins, a process that has been linked to coronary artery disease. The unanticipated large kinetic isotope effects reported here for the tocopherol-mediated oxidation of linoleic and linolenic acids and esters suggests that tunneling makes this process favorable.