Osinskaia L F, Chumakov V N
Biokhimiia. 1980 Feb;45(2):217-27.
It was shown that rat liver mitochondria and microsomes contain NADPH- and NADH-dependent systems of enzymatic lipid peroxidation. Activation of the NAD(P)H-dependent process in mitochondria occurs due to inhibition of membrane binding of Fe3+ and Fe2+ by chelators, since the membrane-bound ions of Fe cannot effectively participate in peroxidation. The activity of enzymatic mitochondrial lipid peroxidation decreases at alkaline values of pH. The Michaelis constant for chelated Fe3+ ions under NAD(P)H-dependent mitochondrial peroxidation is by 1,5 order of magnitude more than for microsomal peroxidation. In terms of the chelators' effect on Fe3+ binding by microsomes and peroxidation, as well as pH and Km for Fe3+ the microsomal NADHL-dependent system of lipid peroxidation is similar to mitochondrial NADPH-systems; however, it differs from the latter in the type of dependence of peroxidation on the amount of membranes. Based on the ability of the NADPH-system of microsomes to produce the superoxide radical which participates in initiation of peroxidation together with Fe ions, it is assumed that the decrease of Km for Fe3+ at NAD(P)H-dependent lipid peroxidation in mitochondria and the NADH-process in microsomes can occur in the presence of exogenous sources of active oxygen production.
结果表明，大鼠肝脏线粒体和微粒体含有依赖NADPH和NADH的酶促脂质过氧化系统。线粒体中依赖NAD(P)H的过程的激活是由于螯合剂抑制了Fe3+和Fe2+与膜的结合，因为与膜结合的Fe离子不能有效地参与过氧化反应。酶促线粒体脂质过氧化的活性在碱性pH值下降低。在依赖NAD(P)H的线粒体过氧化反应中，螯合Fe3+离子的米氏常数比微粒体过氧化反应中的高1.5个数量级。就螯合剂对微粒体结合Fe3+和过氧化反应的影响，以及Fe3+的pH值和Km而言，微粒体依赖NADHL的脂质过氧化系统与线粒体依赖NADPH的系统相似；然而，它在过氧化反应对膜量的依赖类型上与后者不同。基于微粒体的NADPH系统产生超氧自由基并与Fe离子一起参与过氧化反应引发的能力，推测在线粒体中依赖NAD(P)H的脂质过氧化反应和微粒体中依赖NADH的过程中，Fe3+的Km降低可能发生在存在活性氧产生的外源来源的情况下。
