The effect of oxygen on the amplitude of photodriven electron transfer across the lipid bilayer-water interface.
The effect of oxygen on the amplitude of photodriven electron transfer across the lipid bilayer-water interface.
复制标题
氧对穿过脂质双层-水界面的光驱动电子转移幅度的影响。
DOI：
10.1016/s0006-3495(85)83964-3
复制
发表时间：
1985
影响因子：
3.4
通讯作者：
Mauzerall,D
中科院分区：
文献类型：
--
作者：
Ilani,A;Liu,TM;Mauzerall,D
令人惊讶的是，在色素脂质双层中，氧对光电子转移的影响很小，可以追溯到激发态的寿命很短。降低氧浓度大于100倍，受体的半饱和浓度仅降低三倍，并且对受体饱和时观察到的最大光电压没有影响。这适用于镁八乙基卟啉和叶绿素与铁氰化物和甲基紫精作为受体。由于氧在接近碰撞极限时淬灭激发态，反应态的寿命必须很短，小于100 ns。与使光效应饱和相比，需要约100倍更高浓度的受体来淬灭荧光（在脂质体中）。因此，反应态最有可能是三重态。激发态的短寿命是由浓度猝灭引起的，即，它们与基态分子的反应随着颜料浓度的增加，光电压的增加表明，这种在凝聚形式的颜料中的淬灭产生离子，通过阴离子与受体的界面反应导致观察到的光电压。
The surprisingly small effect of oxygen on photoelectron transfer in pigmented lipid bilayers is traced to a short lifetime of the excited states. Decreasing the oxygen concentration by greater than 100-fold decreases the half saturating concentration of acceptor by only threefold and has no effect on the maximum photovoltage observed at acceptor saturation. This holds true for both magnesium octaethylporphyrin and chlorophyll with both ferricyanide and methyl viologen as acceptors. Since oxygen quenches excited states at near the encounter limit, the lifetime of reactive state must be short, less than 100 ns. About 100-fold higher concentrations of acceptor are required to quench the fluorescence (in liposomes) than to saturate the photoeffect. Thus the reactive state is most likely the triplet. The short life of the excited state is caused by concentration quenching, i.e., their reaction with ground state molecules. The increase of photovoltage with increasing pigment concentration shows that this quenching in a condensed form of the pigment produces ions that lead to the observed photovoltage by interfacial reaction of the anion with acceptor.