Scarpa M, Rigo A, Maiorino M, Ursini F, Gregolin C
Biochim Biophys Acta. 1984 Sep 28;801(2):215-9. doi: 10.1016/0304-4165(84)90070-9.
The events accompanying the inhibitory effect of alpha-tocopherol and/or ascorbate on the peroxidation of soybean L-alpha-phosphatidylcholine liposomes, which are an accepted model of biological membranes, were investigated by electron paramagnetic resonance, optical and polarographic methods. The presence of alpha-tocopherol radical in the concentration range 10(-8)-10(-7) M was detected from its EPR spectrum during the peroxidation of liposomes, catalysed by the Fe3+-triethylenetatramine complex. The alpha-tocopherol radical, generated in the phosphatidylcholine bilayer, is accessible to ascorbic acid, present in the aqueous phase at physiological concentrations. Ascorbic acid regenerates from it the alpha-tocopherol itself. A kinetic rate constant of about 2 X 10(5) M-1 X s-1 was estimated from the reaction as it occurs under the adopted experimental conditions. The scavenging effect of alpha-tocopherol on lipid peroxidation is maintained as long a ascorbic acid is present.
通过电子顺磁共振、光学和极谱法研究了α-生育酚和/或抗坏血酸对大豆L-α-磷脂酰胆碱脂质体过氧化的抑制作用所伴随的事件，大豆L-α-磷脂酰胆碱脂质体是生物膜的公认模型。在由Fe3 +-三亚乙基四胺络合物催化的脂质体过氧化过程中，从其EPR光谱中检测到浓度范围为10（-8）-10（-7）M的α-生育酚自由基。在磷脂酰胆碱双层中产生的α-生育酚自由基可被生理浓度存在于水相中的抗坏血酸所接触。抗坏血酸从它再生出α-生育酚本身。根据在采用的实验条件下发生的反应，估计动力学速率常数约为2×10（5）M-1×s-1。只要存在抗坏血酸，α-生育酚对脂质过氧化的清除作用就会保持。
