Dremina E S, Vlasova I I, Vakhrusheva T V, Sharov V S, Azizova O A
Biofizika. 1997 Sep-Oct;42(5):1079-87.
The effect of metal cations on copper-catalyzed lipid peroxidation (LPO) of low density lipoproteins (LDL) was examined. The presence of metal cations in the incubation media containing LDL (0.8 mg protein/ml) and CuSO4 (0-80 microM) influenced on LPO of LDL as evident by the measurement of TBARS. With the concentrations of CuSO4 less than 10 microM, the metal cations caused an increase in LDL peroxidation. Zn2+ appeared to be the most effective inductor, Mn2+ was less effective, and the influence of Ca2+ and Mg2+ was insignificant. With greater CuSO4 concentrations Mg2+ showed no effect on TBARS formation in LDL while the addition of other nontransition metal cations to the incubation mixture led to the inhibition of LDL peroxidation. The capacity for inhibition decreased in the row Mn2+ > Zn2+ > Ca2+ > Mg2+. The possible mechanism explaining these results may be in the competition of metal ions for copper binding sites on LDL. Our results allow to suggest the existence of two types of copper binding sites on LDL, tight-binding sites which are non-effective in LPO and effective weak-binding sites.
研究了金属阳离子对铜催化的低密度脂蛋白（LDL）脂质过氧化（LPO）的影响。在含有LDL（0.8mg蛋白质/ml）和CuSO4（0 - 80μM）的孵育介质中金属阳离子的存在对LDL的LPO有影响，这通过硫代巴比妥酸反应物（TBARS）的测量得以证明。当CuSO4浓度低于10μM时，金属阳离子导致LDL过氧化增加。Zn2 +似乎是最有效的诱导剂，Mn2 +效果较差，而Ca2 +和Mg2 +的影响不显著。当CuSO4浓度更高时，Mg2 +对LDL中TBARS的形成没有影响，而向孵育混合物中添加其他非过渡金属阳离子会导致LDL过氧化受到抑制。抑制能力按Mn2 + > Zn2 + > Ca2 + > Mg2 +的顺序降低。解释这些结果的可能机制可能是金属离子竞争LDL上的铜结合位点。我们的结果表明LDL上存在两种类型的铜结合位点，即对LPO无效的紧密结合位点和有效的弱结合位点。
