Dremina E S, Sharov V S
Biofizika. 1995 Mar-Apr;40(2):335-41.
In order to study the kinetics of lipid peroxidation (LPO) at the stationary Fe2+ concentration the measurement of 2-thiobarbituric acid-reactive substances (TBARS) accumulation along with chemiluminescence (CL) in liposomes in the presence of ascorbic acid was used. It was shown that at 1 mM concentration of ascorbic acid the constant rate of LPO development occurred. In this system the direct determination of LPO rates at different Fe2+ concentrations were performed. The dependence of LPO rate on Fe2+ concentration was bell-shaped with a maximum at 50 microM. Probably, this value corresponds the "critical" ferrous ions concentration in a system. At 500 microM Fe2+ the LPO development was completely inhibited, but the addition of inorganic phosphate was found to start TBARS accumulation and CL development. The increase of phosphate concentration up to 500 microM produced the increase of LPO rate, however, at a higher phosphate concentrations LPO rate decreased. The biphasic effect of phosphate was completely similar to the decrease of Fe2+ concentration from the initial level (500 microM). It was proposed that the effect of phosphate is due to Fe2+ ion chelation in water solution leading to the remove some part of membrane-bound ferrous ions participating in LPO reactions, rather than changing of Fe2+ reactivity.
为了研究在固定Fe2+浓度下脂质过氧化（LPO）的动力学，采用在抗坏血酸存在的情况下，测量脂质体中2-硫代巴比妥酸反应性物质（TBARS）的积累以及化学发光（CL）的方法。结果表明，在抗坏血酸浓度为1 mM时，LPO的发展速率恒定。在该系统中，对不同Fe2+浓度下的LPO速率进行了直接测定。LPO速率对Fe2+浓度的依赖性呈钟形，在50 microM时达到最大值。可能，该值对应于系统中的“临界”亚铁离子浓度。在Fe2+浓度为500 microM时，LPO的发展完全受到抑制，但发现添加无机磷酸盐会引发TBARS的积累和CL的发展。磷酸盐浓度增加到500 microM时，LPO速率增加，然而，在更高的磷酸盐浓度下，LPO速率下降。磷酸盐的双相效应与从初始水平（500 microM）降低Fe2+浓度完全相似。有人提出，磷酸盐的作用是由于其在水溶液中螯合Fe2+离子，导致参与LPO反应的部分膜结合亚铁离子被去除，而不是改变Fe2+的反应活性。
